Sindh Mdcat Mock Paper 2 — Solved Past Paper with Answers

Q1. Complete the sentences by choosing the most appropriate word, from the given lettered choices A to E below:Nearly everyone dreams of building _ ideal house.

• A. Its
• B. Their✓
• C. His
• D. Him
• E. Them

Explanation: In the sentence, 'Nearly everyone dreams of building _ ideal house,' the word 'everyone' is a singular noun. Traditionally, a singular pronoun would follow, such as 'his' or 'her'. However, in modern English, 'their' is often used to maintain gender neutrality. This makes 'their' the most appropriate choice in this context. Other options like 'its' and 'him' do not fit the possessive context, and 'them' is an object pronoun, not a possessive one.

Q2. Complete the sentences by choosing the most appropriate word, from the given lettered choices A to E below:Life _ water, light, a moderate temperature, and a variety of chemical elements.

• A. Finds
• B. Reveals
• C. Designs
• D. Calculates
• E. Requires✓

Explanation: All entities mentioned above are those that are required for us to sustain and survive. Hence the best verb here would be “requires”.

Q3. Choose the correct antonym to the word in capital letters.ASSERTION

• A. Statement
• B. Denial✓
• C. Claim
• D. Unrest
• E. tiring

Explanation: The word Assertion means making a confident and forceful statement of fact or belief. The word that is most nearly opposite in meaning is denial, which involves refusing to accept something as true.

Q4. Complete the sentence by choosing the most appropriate word, from the given lettered choices (A to E) below each. The injured player was taken _ the field.

• A. Of
• B. Off✓
• C. Out
• D. In
• E. By

Explanation: The correct answer is “off” because it effectively conveys the action of removing the injured player from the field. The preposition 'off' indicates a separation or removal from the field, which is appropriate in this context. The other options are incorrect because they do not convey the necessary movement or change in position. 'Of' indicates possession, 'out' suggests leaving an enclosed space, 'in' suggests entering, and 'by' suggests proximity, none of which fit the context of the sentence.

Q5. Identify the word or phrase that needs to be changed for the sentence to be correct:He brought down the tiger with his first shot.

• A. Brought
• B. Down
• C. With
• D. First shot
• E. No error✓

Explanation: The above sentence has no error hence the answer is E.

Q6. Select the word with correct spelling:

• A. Benefited✓
• B. Benefitted
• C. Benifited
• D. Benifitted

Explanation: Benefited: receive an advantage; profit.

Q7. Select the most suitable synonym for the given word:APPALLING

• A. Terrible✓
• B. Appealing
• C. Waning
• D. Snowballing

Explanation: Appalling is something causing immense horror or dismay and is thus synonymous with terrible.

Q8. Choose the correct option.

• A. Samar bought an apple, an orange and an pear.
• B. Samar bought an apple a orange and a pear.
• C. Samar bought an apple, an orange and a pear.✓
• D. Samar bought a apple, an orange and a pear.

Explanation: This option is correct. It correctly uses commas to separate the items in the list ("an apple", "an orange", and "a pear"), and the articles ("an" and "a") are used correctly.

Q9. Identify the tense used in the given sentence: "Everyone shall be reaching by tomorrow."

• A. Present
• B. Past
• C. Future✓
• D. None

Explanation: The given sentence is in future tense indicated by the word " Shall." Therefore, option C is the right choice here.

Q10. “Zymase”- a group of 14 enzymes used in the fermentation of starch, is present in:

• A. Bacteria
• B. Yeast✓
• C. Fungi
• D. Algae
• E. Virus

Explanation: Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide. It occurs naturally in yeasts. Zymase activity varies among yeast strains. Zymase is also the brand name of the drug pancrelipase.

Q11. In heavy smokers the alveoli become enlarged and damaged which reduces the surface area for the exchange of respiratory gases.This condition is called:

• A. Lung cancer
• B. Emphysema✓
• C. Asthma
• D. Bronchitis

Explanation: Emphysema is a chronic respiratory condition often caused by smoking, where the alveoli in the lungs are destroyed and enlarged. This damage leads to a reduction in the surface area available for the exchange of oxygen and carbon dioxide, resulting in breathing difficulties. Unlike emphysema, lung cancer involves the uncontrolled growth of abnormal cells in lung tissues, asthma involves airway inflammation and narrowing, and bronchitis involves inflammation of the bronchial tubes, none of which primarily involve the destruction of alveoli.

Q12. Name the chronic respiratory disorder caused mainly by cigarette smoking.

• A. Respiratory acidosis
• B. Respiratory alkalosis
• C. Emphysema✓
• D. Asthma

Explanation: Emphysema is a chronic respiratory disorder primarily caused by cigarette smoking, leading to damaged lung tissue and breathing difficulties.

Q13. What is the main cause of lung cancer?

• A. Smoking✓
• B. Cough
• C. Pollutants
• D. Mutagens

Explanation: Smoking is the primary cause of lung cancer, responsible for approximately 90% of cases. The chemicals in tobacco smoke cause mutations in lung cells, leading to cancer. Quitting smoking is crucial for reducing lung cancer risk.

Q14. Cancer expands systematically by:

• A. Locally
• B. Systemic
• C. Metastasis✓
• D. Invasion

Explanation: Cancer spreads to distant sites through a process known as metastasis. During metastasis, cancer cells break away from the primary tumor, travel through the bloodstream or lymphatic system, and form new tumors in other organs or tissues. This is distinct from local growth (invasion) and is not accurately described by the term 'systemic' as it specifically involves movement to distant sites.

Q15. How many compounds of tar in tobacco smoke are included in causing cancer?

• A. More than 2
• B. More than 5
• C. More than 8
• D. More than 10✓

Explanation: The correct answer is "D". Tobacco smoke is made up of thousands of chemicals, including at least 70 known to cause cancer. This option suggests that more than ten compounds of tar in tobacco smoke are included in causing cancer. This option is the closest to the truth. The exact number of carcinogenic compounds in tobacco smoke is complex and can vary depending on the type of tobacco and smoking conditions. However, it is well-established that tobacco smoke contains numerous carcinogens, and the actual number is indeed more than ten.

Q16. Erythropoiesis starts in:

• A. Spleen
• B. Red bone marrow✓
• C. Kidney
• D. Liver

Explanation: Erythropoiesis is the formation of red blood cells (erythrocytes) which occurs in the red bone arrow. Proerythroblast is the earliest precursor which gives rise successively to the early erythroblast, intermediate erythroblast and late erythroblast. Then, the nucleus is forced out and a biconcave, enucleated cell called reticulocyte is formed, which is released into blood. In blood, it develops into mature erythrocytes. Red bone marrow, found in certain bones of the body, is the primary site for erythropoiesis. It is responsible for producing red blood cells (erythrocytes), along with other blood cell types like white blood cells and platelets. Red bone marrow contains stem cells known as hematopoietic stem cells that give rise to various blood cell lineages, including red blood cells.

Q17. Doctors use a stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when:

• A. AV node receives a signal from SA node
• B. AV valves open up
• C. Ventricular walls vibrate due to gushing in of blood from atria
• D. Semilunar valves close down after the blood flows into vessels from ventricles✓

Explanation: The second heart sound (S2) is produced by the closure of the semilunar valves (aortic and pulmonary valves) after the ventricles have ejected blood into the aorta and pulmonary artery. This prevents backflow into the ventricles. The other options involve processes that do not produce the second heart sound: the AV node's signal reception is an electrical event without an associated sound; the opening of the AV valves produces the first heart sound (S1); and ventricular wall vibrations, though occurring, are not responsible for the distinct second heart sound.

Q18. In mammals, which blood vessel would normally carry the largest amount of urea?

• A. Hepatic vein✓
• B. Hepatic portal vein
• C. Renal vein
• D. Pulmonary vein

Explanation: Urea is synthesized in the liver during the urea cycle. The hepatic vein drains blood from the liver, so it contains the highest concentration of urea.

Q19. Serum differs from blood in:

• A. Lacking globulins
• B. Lacking albumins
• C. Lacking clotting factors✓
• D. Lacking antibodies.

Explanation: Serum is plasma without clotting proteins like fibrinogen, which are consumed during coagulation.

Q20. Name the blood cells whose reduction in number causes clotting disorder:

• A. Erythrocytes
• B. Leukocytes
• C. Neutrophils
• D. Thrombocytes✓

Explanation: Thrombocytes (platelets) initiate clot formation. A reduced count causes bleeding disorders.

Q21. Which one of the following vectors is used to replace the defective gene in gene therapy?

• A. Adenovirus✓
• B. Cosmid
• C. Ri plasmid
• D. Di plasmid

Explanation: Adenoviruses are efficient vectors for delivering therapeutic genes to a variety of cell types, making them a popular choice for gene therapy. They can introduce the corrected gene into the patient's cells to replace a defective one. Cosmids are used for cloning large DNA sequences and are not typically involved in gene therapy. Ri plasmids are used in plant genetic engineering, and there is no recognized entity called a 'Di plasmid' in the context of gene therapy.

Q22. In Bt cotton, the Bt toxin present in plant tissue as protoxin is converted into active toxin due to:

• A. Action of gut microorganisms
• B. Presence of conversion factors in the insect gut
• C. Alkaline pH of the insect gut✓
• D. Acidic pH of the insect gut

Explanation: The Bt toxin in Bt cotton is initially produced as an inactive protoxin. When ingested by insects, it encounters the alkaline environment of the insect gut, which is crucial for converting the protoxin into its active form. This active toxin then binds to specific receptors in the gut cells, causing cell lysis and ultimately killing the insect. The alkaline pH is the key factor here, not gut microorganisms, specific conversion factors, or an acidic environment, which is why Option C is correct.

Q23. The introduction of t-­DNA into plants involves:

• A. Exposing the plants to cold for a brief period
• B. Allowing the plant roots to stand in water
• C. Infection of the plant by Agrobacterium tumefaciens✓
• D. Altering the pH of the soil and then heat­ shocking the plants.

Explanation: The correct answer is the infection of the plant by Agrobacterium tumefaciens. This bacterium naturally transfers t-DNA from its Ti plasmid into the plant genome, a process utilized in biotechnology to introduce new genetic material into plants. The other options describe methods that do not relate to the mechanism of t-DNA introduction: cold exposure, standing in water, and altering pH followed by heat shock are not part of this genetic transformation process.

Q24. Golden rice is a genetically modified crop plant where the incorporated gene is meant for the biosynthesis of:

• A. Omega 3
• B. Vitamin A✓
• C. Vitamin B
• D. Vitamin C

Explanation: Golden rice is genetically engineered to produce beta-carotene, a precursor to Vitamin A, with the goal of addressing Vitamin A deficiency, particularly in regions where diets are low in this essential nutrient. Omega 3, Vitamin B, and Vitamin C are not the nutrients for which golden rice has been modified. Omega 3 is a fatty acid, while Vitamin B and C are other essential vitamins not related to the genetic modifications in golden rice.

Q25. Which part of the tobacco plant is infected by Meloidogyne incognita?

• A. Stem
• B. Root✓
• C. Flower
• D. Leaf

Explanation: The correct answer is Root. Meloidogyne incognita, commonly known as the root-knot nematode, primarily infects the roots of plants, including tobacco. It causes the formation of galls or 'knots' which impede the plant's ability to absorb water and nutrients effectively, leading to reduced growth and yield. The other parts of the plant, such as the stem, flower, and leaf, are not directly infected by this nematode, although they may show secondary effects due to compromised root function.

Q26. Which kind of therapy was given in 1990 to a four­ year­ girl with Adenosine Deaminase (ADA) enzyme deficiency?

• A. Gene therapy✓
• B. Chemotherapy
• C. Immunotherapy
• D. Radiation therapy

Explanation: Gene therapy was the treatment given in 1990 to a four-year-old girl with Adenosine Deaminase (ADA) deficiency. This type of therapy focuses on correcting genetic problems by inserting genes into a patient's cells. In the case of ADA deficiency, gene therapy was used to insert a healthy copy of the ADA gene into the child's cells to compensate for the defective gene, thereby restoring the function of the enzyme. On the other hand, chemotherapy, immunotherapy, and radiation therapy are primarily used for cancer treatment and are not applicable for treating genetic enzyme deficiencies.

Q27. Nitrogenous waste products are eliminated mainly as:

• A. Urea in tadpole and ammonia in adult frog
• B. Ammonia in tadpole and urea in adult frog✓
• C. Urea in both tadpole and adult frog
• D. Urea in tadpole and uric acid in adult frog

Explanation: The correct answer is that tadpoles excrete ammonia, and adult frogs excrete urea. Tadpoles live in an aquatic environment where ammonia, a soluble nitrogenous waste, can be easily excreted into the surrounding water. Adult frogs, however, live in both aquatic and terrestrial environments and excrete urea, which is less toxic and conserves water compared to ammonia. This adaptation is crucial for their survival outside water. The other options are incorrect because they either reverse the excretion process of tadpoles and adult frogs or introduce uric acid, which is not the primary waste product for frogs.

Q28. The basic functional unit of human kidney is

• A. Nephridia
• B. Loop of Henle
• C. Nephron✓
• D. Pyramid

Explanation: The correct answer is the nephron. Nephrons are microscopic structures in the kidney that filter blood to form urine. Each kidney contains about a million nephrons, which regulate water and solute levels. Nephridia are found in invertebrates, the Loop of Henle is part of the nephron but not the functional unit itself, and pyramids are regions in the kidney containing nephrons.

Q29. A condition of failure of kidney to form urine is called:

• A. Aneuria✓
• B. Deamination
• C. Uremia
• D. Oliguria

Explanation: The correct answer is Anuria. Anuria is a condition where the kidneys fail to produce urine, which can be a serious indicator of kidney failure. Deamination is related to the breakdown of amino acids in the liver and not related to urine formation. Uremia occurs when waste products build up in the blood due to kidney dysfunction, but it doesn't define the lack of urine production. Oliguria refers to reduced urine output, not a complete absence as seen in anuria.

Q30. The net pressure gradient that causes the fluid to filter out of the glomeruli into the capsule is:

• A. 50 mm/HG
• B. 75 mm/HG✓
• C. 20 mm/HG
• D. 30 mm/HG

Explanation: The net pressure gradient, or net filtration pressure, is the force that drives the fluid from the glomeruli into the Bowman's capsule. This is typically around 20 mm/HG. It is calculated by taking the glomerular hydrostatic pressure (usually around 50 mm/HG) and subtracting both the glomerular osmotic pressure and the capsular hydrostatic pressure. The other options are incorrect because they either represent only part of the forces involved (like the hydrostatic pressure alone) or are values that do not align with the physiological conditions within the glomeruli.

Q31. What will happen if the stretch receptors of the urinary bladder wall are totally removed?

• A. Micturition will continue
• B. Urine will continue to collect normally in the bladder
• C. There will be no micturition✓
• D. Urine will not collect in the bladder

Explanation: The stretch receptors in the urinary bladder wall are crucial for initiating the micturition reflex. When the bladder fills with urine, these receptors send signals to the brain, which then triggers the urge to urinate. If these receptors are removed, the brain does not receive the necessary signals to initiate micturition, resulting in the inability to urinate voluntarily. This means that although urine can still accumulate in the bladder, the act of urination will not occur without the conscious effort or assistance. Option A is incorrect because micturition cannot continue without the receptor signals. Option B is misleading as it does not address the inability to urinate. Option D is incorrect since urine collection is independent of stretch receptor functionality.

Q32. A characteristic common in humans and adult frogs is:

• A. Four chambered heart
• B. Internal fertilization
• C. Nucleated RBCs
• D. Ureotelic mode of excretion✓

Explanation: Both humans and frogs excrete nitrogen mainly as urea.

Q33. Removal of proximal convoluted tubule from the nephron will result in:

• A. No change in quality and quantity of urine
• B. No urine formation
• C. More diluted urine✓
• D. More concentrated urine

Explanation: The proximal convoluted tubule is crucial for the reabsorption of water, ions, and nutrients from the filtrate back into the bloodstream. If this section of the nephron is removed, the kidney loses much of its ability to reabsorb these substances, leading to the production of a larger volume of more diluted urine. Option A is incorrect because removing the tubule significantly changes urine composition. Option B is incorrect as urine formation involves multiple nephron segments; thus, it doesn't stop entirely. Option D is incorrect because the urine becomes less concentrated due to the lack of reabsorption, not more.

Q34. The part of the nephron involved in active reabsorption of sodium is:

• A. Distal convoluted tubule
• B. Proximal convoluted tubule✓
• C. Bowman's capsule
• D. Descending limb of Henle's loop

Explanation: PCT reabsorbs sodium actively along with water and other solutes.

Q35. The viruses are:

• A. Cellular
• B. Prokaryotes
• C. Non-cellular✓
• D. Eukaryotes
• E. Visible with naked eye

Explanation: Viruses are classified as non-cellular because they lack the cellular structures that define living cells, such as a cell membrane, cytoplasm, and organelles. Instead, they consist of genetic material (either DNA or RNA) surrounded by a protein coat called a capsid. Unlike cellular organisms, viruses cannot perform metabolic processes or reproduce on their own; they must infect a host cell to replicate. This distinguishes them from cellular life forms, including prokaryotes and eukaryotes.Option A (Cellular) is incorrect because viruses do not have the structures that define cellular life. Option B (Prokaryotes) is incorrect because viruses do not fit the definition of prokaryotic cells, which have a cell membrane and cytoplasm. Option D (Eukaryotes) is incorrect because viruses do not have the complex structures found in eukaryotic cells. Option E (Visible with naked eye) is incorrect because viruses are too small to be seen without specialized equipment.

Q36. Which of the following describes the movements involved in breathing out?

• A. Option A
• B. Option B✓
• C. Option C
• D. Option D

Explanation: Breathing out involves a decrease in the volume of the chest this occurs when ribs move downwards and inwards, the diaphragm moves upwards. The opposite of these movements increases in chest volume and involves movements of ribs upwards and outwards.

Q37. Which of the following is not true about the human immunodeficiency virus?

• A. Retrovirus
• B. It is surrounded by an envelope
• C. It does not cause AIDS✓
• D. It causes a deficiency in the human immune system

Explanation: HIV is the virus that causes AIDS (Acquired Immunodeficiency Syndrome). It attacks and weakens the immune system over time, leading to the development of AIDS in untreated individuals. It is also an enveloped virus.

Q38. The diagram shows a molecule. Which substance might include the above molecule?

• A. Cellulose
• B. Serine
• C. Glucose
• D. Alanine✓

Explanation: The given molecule is identified as an amino acid due to the presence of an alpha carbon bonded to an amino group, a carboxyl group, and a side chain. The side chain in the molecule is a methyl group (-CH3), which is specific to alanine, making option D the correct answer.Option A, Cellulose, is a carbohydrate, not an amino acid, as it consists of glucose units. Option B, Serine, is an amino acid but has a hydroxymethyl group instead of a methyl group. Option C, Glucose, is a simple sugar and lacks the functional groups characteristic of amino acids.

Q39. An example of passive acquired immunity is?

• A. Use of polio vaccine
• B. Passing of certain antibodies to the foetus by the pregnant women
• C. Inoculation of antitoxin in the case of puncture wound
• D. Both B and C✓

Explanation: Passive immunity is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system.

Q40. During the first three steps of glycolysis, glucose is converted to Fructose 1, 6-diphosphate by the rearrangement of the molecule and addition of two phosphate groups. The phosphate comes from?

• A. Phospholipids of the membrane
• B. ADP
• C. Inorganic phosphates
• D. ATP✓

Explanation: During the initial steps of glycolysis, ATP molecules are crucial for facilitating the phosphorylation of glucose. In the first step, glucose is phosphorylated by ATP to form glucose-6-phosphate, catalyzed by the enzyme hexokinase. In the third step, another ATP molecule donates a phosphate group to fructose 6-phosphate, forming fructose 1,6-diphosphate through the action of the enzyme phosphofructokinase. These phosphorylation steps are essential for the continuation of glycolysis and subsequent energy production. The other options, like phospholipids and ADP, do not contribute phosphate groups in this metabolic pathway, while inorganic phosphates are not the direct source of phosphorylation in these steps.

Q41. The dark reactions of photosynthesis are characterized by:

• A. Synthesis of ATP, O2 and NADH
• B. Utilization of ATP, CO2 and NADPH✓
• C. Electron transfer from NADPH to RuBP
• D. Carbon dioxide transfer from RuBP to glucose

Explanation: Dark reaction is also called carbon-fixing reaction. It is a light-independent process in which sugar molecules are formed from carbon dioxide, water molecules, ATP, and NADPH(products from the light-dependent reaction). The dark reaction occurs in the stroma of the chloroplast, where they utilize the products of the light reaction.

Q42. Which of the following is correctly matched?

• A. AF, BG, CJ, DI, EH
• B. AH, BI, DF, CG, EJ✓
• C. AJ, BI, CH, DG, EF
• D. AH, BF, DG, CI, EJ

Explanation: To solve this quickly just match one or two organelles to their correct function,crossing out the wrong options while doing so. Peroxisomes carry out detoxification of alcohol which is only in option B so we can easily choose it,no other options have DF. To check others, we know that smooth ER deals with cholesterol and fats that is why E goes with J.Ribosomes carry out protein synthesis.Centrioles form astral rays.Lysosomes destroy foreign particles.Hence,AH, BI, DF, CG, EJ is correct.

Q43. All of the following protect the body against the entrance of germs except:

• A. Tears
• B. Mucous membranes
• C. Ciliated cells
• D. Red blood cells,✓

Explanation: Red blood cells are responsible for transporting O2 via hemoglobin stored in them from the lungs to the body's cells and tissues. Options A, B, and C are incorrect because they are physical barriers (part of the first line of defense) that protect our body from germs.

Q44. The table shows the characteristics of the blood in one vessel. Which vessel contains blood with these characteristics?

• A. Aorta✓
• B. Pulmonary artery
• C. Pulmonary vein
• D. Vena cava

Explanation: The aorta carries oxygen-rich blood at high pressure from the left ventricle to systemic circulation.

Q45. Which part of the heart is known as the Left Ventricle that helps to supply oxygenated blood to almost the whole body?

• A. 6✓
• B. 1
• C. 3
• D. 4

Explanation: The left ventricle of the heart is located at position 6 in the figure. It is responsible for pumping oxygenated blood to the entire body through the aorta. This thick-walled and muscular chamber generates high pressure to maintain blood flow throughout the body. Other marked points include the superior vena cava (2), which brings deoxygenated blood from the upper body to the right atrium of the heart. The aorta (1) carries oxygenated blood from the left ventricle to the rest of the body. The right atrium (3) receives deoxygenated blood from the body and pumps it into the right ventricle. The tricuspid valve (4) separates the right atrium and right ventricle. The right ventricle (5) is the chamber of the heart that receives deoxygenated blood from the right atrium and pumps it to the lungs for oxygenation, while the bicuspid valve (7) separates the left atrium and left ventricle.

Q46. Arrange the following according to the level of protein structures:a) lysozyme, b) haemoglobin, c) Individual chains of insulin, d) hairs

• A. d, a, c, b
• B. a, b, c, d
• C. d, c, b, a
• D. c, d, a, b✓

Explanation: The correct order is c, d, a, b:Insulin: This is a hormone composed of two peptide chains with a specific amino acid sequence, representing its primary structure.Hair (Keratin): The structural protein keratin in hair forms alpha-helices, indicative of a secondary structure.Lysozyme: This enzyme has a complex three-dimensional folding, typical of a tertiary structure.Hemoglobin: Composed of four subunits, hemoglobin exemplifies a quaternary structure.Other options incorrectly sequence the proteins based on their structural complexity.

Q47. Which of the following bones are present in the palm of the hand:

• A. Carpals
• B. Metacarpals✓
• C. Phalanges
• D. Tarsal
• E. Radius

Explanation: The human forelimbs each consist of 30 bones: The humerus, which forms a ball and socket joint with the scapula, and two long parallel bones, the radius and ulna, at its distal end. The radius and ulna join the wrist with eight small carpal bones, which articulate with five metacarpals of the palm. From the palm extend the fingers containing 14 small bones called phalanges, arranged in 5 rows, one row in each finger. The relevant detail for this question is that the bones of the palm are called metacarpals, hence option B is correct.

Q48. Lysosomes are also called:

• A. Suicide Sacs✓
• B. Chondriosome
• C. Storage organelle
• D. Dicytosome
• E. Power house of a cell

Explanation: Lysosomes are sphere-shaped sacs filled with hydrolytic enzymes that have the capability to break down many types of biomolecules. Lysosomes are known as suicide sacs of the cell because they contain lytic enzymes capable of digesting cells and unwanted materials.

Q49. When a physician elicits the knee-jerk reflex by tapping deep tendons in the knee, the normal response is for the lower leg to swing forward. When this happens:

• A. Muscles in the front of the thigh are contracting, and muscles in the back of the thigh are relaxing✓
• B. Muscles in the front of the lower leg are contracting, and muscles in the back of the lower leg are relaxing
• C. Muscles in the back of the thigh are contracting, and muscles in the front of the thigh are relaxing
• D. Muscles in the back of the lower leg are contracting and muscles in the front of the lower leg are relaxing
• E. None of the above

Explanation: In the knee-jerk reflex, tapping the patellar tendon causes the quadriceps, located at the front of the thigh, to contract. This contraction results in the extension of the lower leg, moving it forward. Simultaneously, the hamstrings at the back of the thigh relax to facilitate this movement. This reflex is an example of a monosynaptic reflex arc, where sensory neurons are directly connected to motor neurons in the spinal cord, allowing for a rapid response. The incorrect options involve muscles of the lower leg or the opposite muscle action, which do not contribute to the observed reflex action.

Q50. Which one of the following organelles is required for aerobic respiration?

• A. Nucleus
• B. Mitochondrion✓
• C. Endoplasmic Reticulum
• D. Plastids
• E. Cytoskeleton

Explanation: The correct answer is the mitochondrion, as it is the site where aerobic respiration takes place, producing ATP through the citric acid cycle and the electron transport chain. Other organelles like the nucleus, endoplasmic reticulum, plastids, and cytoskeleton play vital roles in the cell but are not directly involved in the energy production processes of aerobic respiration.

Q51. Pituitary gland releases _ hormone and _ hormone while ovaries produce _ and progesterone.

• A. Follicle-stimulating and luteinizing, estrogen✓
• B. Estrogen and follicle-stimulating, luteinizing
• C. Luteinizing and estrogen, follicle-stimulating
• D. Follicle-stimulating and estrogen, luteinizing

Explanation: The pituitary gland is responsible for releasing the follicle-stimulating hormone (FSH) and luteinizing hormone (LH), both of which play key roles in regulating the reproductive processes. The ovaries, on the other hand, produce estrogen and progesterone, which are crucial for the development and regulation of the female reproductive system. Options B, C, and D incorrectly assign estrogen to the pituitary gland or misplace the order of the hormones.

Q52. The sexually transmitted disease, which can affect both the male and the female genitals and may damage the eyes of babies born of infected mothers is:

• A. AIDS
• B. Hepatitis
• C. Gonorrhoea✓
• D. All of these

Explanation: Gonorrhea is a bacterial infection. This is a sexually transmitted infection caused by the bacterium Neisseria gonorrhoeae. This disease is often transmitted to the foetus while birth from an infected mother. The baby which is born gets infected with this disease. The common symptom which is observed is eye infections. This type of infections may result in blindness. They may also result in blood and joint infections. Thus, the correct answer is option C.

Q53. The duration of the menstrual cycle is how many days on average?

• A. 25
• B. 26
• C. 27
• D. 28✓

Explanation: The length of the menstrual cycle varies from woman to woman, but the average is to have periods every 28 days. Regular cycles that are longer or shorter than this, from 21 to 40 days, are normal.

Q54. Consider the following statements about biological communities.I. Their members share a common gene poolII. The community remains stable even though some physical aspect of the environment may undergo a changeIII. It consists of all the populations living in a particular area.IV. A community interacts with a non-living environment and both function together to form an ecosystemWhich two of the above statements are true?

• A. 1 and 2
• B. 1 and 3
• C. 2 and 4
• D. 2 and 3
• E. 3 and 4✓

Explanation: Different living and nonliving things in a single habitat form a single community. Since different species are present they have different characteristics so the gene pool is not the same. Change in the environment does cause a change in the balance of genes in the environment so the community does not remain stable.The last two statements iii and iv are right that as previously mentioned the community is all the population living in a particular area. Secondly, the community involves biotic(living) and abiotic(non-living) factors interacting with one another.

Q55. Joints found at the vertebrae are:

• A. Gliding joints✓
• B. Sliding joints
• C. Partially moveable joints
• D. Fixed joints
• E. Pivot joints

Explanation: Gliding joints are present between vertebrates.

Q56. The follicle cells, after release of the egg, are modified to form a special structure called:

• A. Endometrium
• B. Perimetrium
• C. Corpus Luteum✓
• D. None of these

Explanation: After the release of the egg (ovulation) from a mature ovarian follicle, the remaining follicle cells undergo a transformation to form a structure known as the corpus luteum. The corpus luteum plays a crucial role in the menstrual cycle and early pregnancy. The corpus luteum is a temporary endocrine structure that develops from the ruptured follicle. It secretes hormones, primarily progesterone and some estrogen, which are essential for the maintenance of the uterine lining (endometrium) during the second half of the menstrual cycle. These hormones help prepare the uterus for a potential pregnancy.

Q57. Where in the female reproductive system are thousands of eggs found?

• A. Ovaries✓
• B. Vagina
• C. Fallopian tubes
• D. Uterus

Explanation: Option A is correct since thousands of eggs are found in the ovaries of the female reproductive system.The ovaries are a pair of small, almond-shaped organs located on either side of the uterus in the female reproductive system.

Q58. When a female ovulates, in which phase of the division is the oocyte?

• A. Anaphase I
• B. Prophase I
• C. Metaphase I
• D. Metaphase II✓

Explanation: After ovulation, the oocyte is arrested in metaphase of meiosis II until fertilization.

Q59. After fertilization the zygote increases in size and travels down the fallopian tube to become embedded in the walls of the womb. This process is called:

• A. Ovulation
• B. Implantation✓
• C. Conception
• D. Menstruation

Explanation: After fertilization, the zygote undergoes a series of cell divisions, forming a structure known as a blastocyst. The blastocyst then travels down the fallopian tube and eventually reaches the uterus. The process by which the blastocyst becomes embedded in the walls of the uterus is called implantation. Implantation generally occurs around 6-10 days after fertilization. The embryo, at this stage, is a multicellular structure, and the process of implantation marks the beginning of the embryonic stage of development. Once implanted, the cells of the blastocyst continue to differentiate, and the early structures of the developing fetus begin to form.

Q60. What type of immunity is achieved by injecting antibodies/antiserum/anti-venom serum?

• A. Active immunity
• B. Artificially induced immunity
• C. Passive immunity✓
• D. Naturally induced immunity

Explanation: Two types of immunity exist - active and passive: Active immunity occurs when our own immune system is responsible for, protecting us from a pathogon. Passive immunity occurs when we are protected from a pathogen by immunity gained from someone else.

Q61. T-lymphocytcs recognize antigen and attack microorganisms or transplanted organ and tissues. The effect is called:

• A. Cell-mediated response✓
• B. Active immunity
• C. Humoral immune response
• D. Passive immunity

Explanation: The humoral immune system deals with antigens from pathogen, that are freely circulating, or outside the infected cells. Cellular immunity occurs inside infected cells and is mediated by T lymphocytes.

Q62. Antibodies are proteins and made up of how many polypeptide chains

• A. One
• B. Two
• C. Three
• D. Four✓

Explanation: Antibodies are immune system-related proteins called immunoglobulins. Each antibody consists of four polypeptide chains 2 heavy chains and 2 light chains joined together to form Y Y-shaped molecule. Hence opt D is the right choice here. Each antibody has a variable region and a constant region. The variable region is composed of 110-130 amino acids which gives the antibody its specificity to bind to antigen. The variable region consists of the end of both light and heavy chains.

Q63. Which part of the antibody recognizes the antigen during immune response?

• A. Heavy part
• B. Light part
• C. Constant part
• D. Variable part✓

Explanation: Antibodies are immune system-related proteins called immunoglobulins. Each antibody consists of four polypeptide chains 2 heavy chains and 2 light chains joined together to form Y Y-shaped molecule. Each antibody has a variable region and a constant region. The variable region is composed of 110-130 amino acids which gives the antibody its specificity to bind to antigen. The variable region consists of the end of both light and heavy chains.

Q64. How many meninges cover the human brain?

• A. 5
• B. 4
• C. 3✓
• D. 2
• E. 1

Explanation: There are three layers of meninges around the brain and spinal cord. The outer layer, the dura mater, is tough, white fibrous connective tissue. The middle layer of meninges is the arachnoid, a thin layer resembling a cobweb with numerous threadlike strands attaching it to the innermost layer.

Q65. Booklungs serve the function of respiration in:

• A. Scorpion✓
• B. Earthworm
• C. Frog
• D. Cockroaches

Explanation: A book lung is a type of respiration organ used for atmospheric gas exchange that is present in many arachnids, such as scorpions and spiders. Each of these organs is located inside an open ventral abdominal, air-filled cavity (atrium) and connects with the surroundings through a small opening for the purpose of respiration.

Q66. The following are all features of eukaryotic cells:I. chloroplastII. peroxisomeIII. lysosomeIV. mitochondrionv. nucleusWhich of these has a double membrane?

• A. I, II and IV
• B. I, III and V
• C. I, IV and V✓
• D. II, III and V
• E. II, III and IV

Explanation: Chloroplasts, mitochondria, and the nucleus are unique in that they all have double membranes, which are essential for their respective functions in energy conversion and genetic protection. Chloroplasts facilitate photosynthesis, mitochondria are the powerhouses of the cell, and the nucleus houses genetic material. In contrast, peroxisomes and lysosomes are single-membrane organelles involved in detoxification and digestion, respectively, and do not require a double membrane for their functions. Therefore, the correct answer is I, IV, and V.

Q67. The water content of mammalian blood is regulated by antidiuretic hormone(ADH). In which part of the nephron does regulation occur ?

• A. The ascending limb of the loop of Henle
• B. The collecting duct✓
• C. The descending limb of the loop of Henle
• D. The proximal convoluted tubule

Explanation: Antidiuretic hormone (ADH) acts on the collecting duct of the nephron to increase water reabsorption, thereby regulating blood water content and concentrating urine.

Q68. As an essential element in living organisms, _ ion is playing an important role in insulin secretion, the release of neurotransmitters, muscle contraction, and heartbeat regulation.

• A. Sodium
• B. Potassium
• C. Calcium✓
• D. Chloride

Explanation: Calcium ions are critical in facilitating the release of neurotransmitters and insulin. They enter cells in response to specific signals and promote vesicular transport to the cell membrane, culminating in exocytosis. Additionally, calcium ions interact with proteins like troponin, playing a pivotal role in muscle contraction. Sodium and potassium are essential for nerve impulse transmission, while chloride maintains fluid and pH balance but does not directly influence insulin secretion or neurotransmitter release.

Q69. The propulsive movement of the gastrointestinal tract (GI tract) is:

• A. Peristalsis✓
• B. Epiglottis
• C. Antiperistalsis
• D. Anus
• E. None of these options

Explanation: Peristalsis is the contraction of muscle tissue that helps move and break down foodstuffs. The walls of the alimentary canal include layers of smooth muscle controlled by the autonomic nervous system. The alternating contraction and relaxation of these muscles is called peristalsis.

Q70. The diagram represents the human respiratory system. While inhalation, which of the labelled muscles contract?

• A. X only
• B. X and Y only
• C. X and Z only
• D. Y and Z only✓
• E. X, Y and Z

Explanation: During inhalation, the diaphragm (labelled as Z) and the external intercostal muscles (labelled as Y) contract to allow the lungs to expand and fill with air. The intercostal muscles labelled as X do not contract during this process; they relax. Hence, the correct answer is option D: Y and Z only. Options involving X are incorrect because X does not contract during inhalation.

Q71. In birds the male is the homogametic sex. A male bird showing the recessive trait was mated with a female showing the dominant trait of a characteristic governed by a pair of alleles which are sex-linked. What is the probability that the male offspring will show the dominant trait?

• A. 0
• B. 0.25
• C. 0.50
• D. 0.75
• E. 1.00✓

Explanation: In this problem, we are dealing with a sex-linked trait where the male parent (XbY) carries the recessive allele (b), and the female parent (XBXB) has two dominant alleles (B). The key is to recognize that in birds, males are homogametic, meaning they have two identical sex chromosomes (XY), while females have two different sex chromosomes (XX).The cross between the male (XbY) and the female (XBXB) yields the following gametes:Xb from the male and XB from the female leads to XbXB (female with dominant trait)Xb from the male and XB from the female leads to XbXB (female with dominant trait)Y from the male and XB from the female leads to XBY (male with dominant trait)Y from the male and XB from the female leads to XBY (male with dominant trait)Thus, all male offspring (XBY) will inherit the dominant allele from the mother, resulting in a probability of 1.00 that they will express the dominant trait.The other options are incorrect because they misinterpret the inheritance pattern and the genotypes of the parents involved in the cross.

Q72. The diagram shows some of the muscles and bones of the human arm.

• A. The tricep contracts to bend the elbow and the bicep relaxes.
• B. The bicep contracts to straighten the elbow and the tricep relaxes.
• C. The tricep contracts to straighten the elbow and the bicep relaxes.✓
• D. The bicep contracts to bend the elbow and the tricep relaxes.
• E. Both A and C are correct.

Explanation: The correct answer is that the tricep contracts to straighten the elbow and the bicep relaxes. In the human arm, the tricep and bicep are antagonistic muscles, meaning they work in opposition to each other to create movement. When the tricep contracts, it exerts force on the bones of the arm, causing the elbow to extend or straighten. During this action, the bicep must relax to allow the movement to occur smoothly. Option A is incorrect because the tricep does not bend the elbow; the bicep is responsible for bending the elbow by contracting. Option B is incorrect because the bicep does not straighten the elbow; that is the function of the tricep. Option D describes the action of bending the elbow, which is not the focus of the question about straightening the elbow. Option E is incorrect because it includes Option A, which is not correct.

Q73. Identify the bones in which the connecting joints are freely movable?

• A. Ankle
• B. Wrist
• C. Vertebrae
• D. Elbow
• E. All of the above except vertebrae✓

Explanation: There are six types of freely movable joints. Namely, ball and socket joint, hinge joint, pivot joint, condyloid joint, saddle joint, and gliding joint. The ankle joint is a hinge-type joint. The wrist is a condyloid joint. Joints of the vertebrae are cartilaginous joints that allow gliding. The elbow joint is a hinge joint. Thus, all the options are examples of freely movable joints except vertebrae.

Q74. Nutritional deficiency ( vitamin D ) results in softening of the bones. This disease is called?

• A. Rickets✓
• B. Cleft palates
• C. Microcephaly
• D. Down syndrome

Explanation: Rickets is a condition that primarily affects children and is caused by a deficiency in vitamin D. Vitamin D is essential for calcium and phosphate absorption in the body, which are critical for healthy bone formation. Without adequate vitamin D, bones become soft and weak, leading to symptoms such as bowed legs and stunted growth. The other options are distinct medical conditions that do not involve vitamin D deficiency or bone softening. Cleft palate is a structural birth defect, microcephaly is a condition affecting brain size, and Down syndrome is a genetic disorder.

Q75. Which bones meet at the elbow joint, and what kind of movement do they allow?

• A. Option A
• B. Option B
• C. Option C
• D. Option D✓

Explanation: At the elbow joint, the ulna and humerus meet, and they cause back-and-forth movement of the forearm. At the shoulder joint, the humerus and scapula meet, and there they cause full axial movement.

Q76. What is the correct sequence of the bones in the arm of a mammal, from the hand to the shoulder?

• A. Phalanges -> Carpal -> Humerus -> Radius and Ulna -> Scapula
• B. Phalanges -> Radius and Ulna -> Carpal -> Humerus -> Scapula
• C. Phalanges -> Carpal -> Radius and Ulna -> Humerus -> Scapula✓
• D. Carpal -> Phalanges -> Radius and Ulna -> Humerus -> Scapula

Explanation: In a mammalian arm, the correct sequence of bones from the hand to the shoulder is: Phalanges -> Carpal -> Radius and Ulna -> Humerus -> Scapula. The Phalanges are the bones of the fingers, followed by the Carpal bones forming the wrist. The Radius and Ulna are the two bones of the forearm, the Humerus is the upper arm bone, and the Scapula is the shoulder blade. Incorrect sequences either misplace the Carpal bones, the Humerus, or the Radius and Ulna.

Q77. Which one is NOT true for coordination in animals?

• A. Transmission by the nervous system is short-lived, whereas transmission by the hormonal system is long-lasting
• B. The nervous system uses electrical impulses to send signals through neurons, whereas hormonal coordination uses chemical messengers transported in the blood
• C. Responses are often permanent in the hormonal system, but temporary and reversible in the nervous system
• D. In the nervous system, secretory chemicals are released in the blood, while in the hormonal system, secretory chemicals are released in extracellular fluids✓

Explanation: The correct answer is Option D. In the nervous system, neurotransmitters are released at synapses between neurons, not into the bloodstream. Hormones, however, are released into the blood by endocrine glands. The other options correctly describe the characteristics of the nervous and hormonal systems in terms of signal duration, nature of transmission, and response permanence.

Q78. Which type of bonds are never formed when a substrate fits into the active site of an enzyme?

• A. Hydrogen bonds
• B. Ionic interactions
• C. Hydrophobic interactions
• D. Covalent linkages✓

Explanation: The correct answer is Covalent linkages because these bonds involve a strong and permanent connection between atoms, which is not typical during the transient interaction of a substrate with an enzyme's active site. Enzymes typically bind substrates through weaker interactions like hydrogen bonds, ionic interactions, and hydrophobic interactions, which facilitate the temporary nature of enzyme-substrate complexes. The other options—hydrogen bonds, ionic interactions, and hydrophobic interactions—are all types of interactions that can indeed occur as substrates fit into the active site, making them incorrect choices for this question.

Q79. An activated enzyme made of polypeptide chain and a cofactor is?

• A. Substrate
• B. Coenzyme
• C. Apoenzyme
• D. Holoenzyme✓

Explanation: An activated enzyme made of a polypeptide chain and a cofactor is referred to as a "holoenzyme." The holoenzyme is the complete, catalytically active form of an enzyme. The holoenzyme structure ensures that the enzyme is in its active conformation and is capable of facilitating the desired biochemical reactions.

Q80. Enzymes are _ in nature.

• A. Carbohydrates
• B. Proteins✓
• C. Lipids
• D. Vitamins

Explanation: Enzymes are primarily proteins that serve as biological catalysts, facilitating and accelerating biochemical reactions by lowering the activation energy required for those reactions. They are essential for various metabolic processes and are highly specific to the substrates they bind to.While carbohydrates, lipids, and vitamins play crucial roles in biological systems, they do not function as enzymes. Carbohydrates provide energy and structural support, lipids are involved in energy storage and membrane structure, and vitamins are essential micronutrients required for numerous physiological functions but do not act as catalysts in reactions.

Q81. Ileum is about _ long:

• A. 3.6 centimeters
• B. 3.6 millimeters
• C. 3.6 inches
• D. 3.6 meters✓
• E. 3.6 kilometers

Explanation: The ileum is about 3.6 meters (11.5 feet) long (or about three-fifths the length of the small intestine) and extends from the jejunum (the middle section of the small intestine) to the ileocecal valve, which empties into the colon (large intestine).

Q82. The reaction involved in chemotrophic nutrition is:

• A. 6CO2 + 12H2O + light + chlorophyll -> C6H12 + 6H2O + 6CO2
• B. 2H2S + CO2 + light -> (CH2O)n + H2O + 2S
• C. NH4 + 3O2 + light -> 2NO2 + 2H2O + 4H+ + energy✓
• D. CH3COOH + enzyme -> CH3CHO + CO2
• E. 5GA3P + 3ATP -> 3RuBP + 2Pi

Explanation: The word Chemoautotrophic nutrition means energy produced through chemical reactions taking place. The primary work is on inorganic compounds used to synthesise different organic compounds. The reaction involved in chemotrophic nutrition is: NH4 + 3O2 + light -> 2NO2 + 2H2O + 4H+ + energy

Q83. A psychological condition usually seen in girls and young women, with loss of appetite, is:

• A. Obesity
• B. Malnutrition
• C. Anorexia Nervosa✓
• D. Dyspepsia
• E. Peptic ulcer

Explanation: Anorexia nervosa is a psychological disorder primarily affecting girls and young women, characterized by an intense fear of gaining weight and a distorted body image, leading to severe food intake restriction and loss of appetite. Unlike the other conditions listed, anorexia is specifically psychological and affects the demographic in question. Obesity is more about excessive weight gain, malnutrition is a broad term for nutrient deficiencies, dyspepsia is a digestive issue, and peptic ulcers are physical conditions of the digestive system.

Q84. Living things that would be the first to experience adverse effects if large amounts of carbon dioxide were taken out of the biosphere are:

• A. Decomposers (e.g., bacteria and fungi)
• B. Producers (e.g., green plants)✓
• C. Primary consumers (e.g., mice)
• D. Secondary consumers (e.g., snakes)
• E. Tertiary consumers (e.g., hawks)

Explanation: Producers are the only organisms that directly use carbon dioxide from the atmosphere for the process of photosynthesis, converting it into energy and oxygen. If carbon dioxide levels were to drop significantly, producers would be the first to suffer since they require it for their survival. Decomposers, primary consumers, secondary consumers, and tertiary consumers rely on the flow of energy and carbon through the food chain, making producers the foundational element. Without sufficient carbon dioxide, the producers cannot perform photosynthesis, affecting the entire ecosystem above them.

Q85. The diagram shows the teeth of the lower jaw of a human. Which tooth is an incisor?

• A. A
• B. B✓
• C. C
• D. D

Explanation: Incisors: These are the sharp, flat teeth at the front of your mouth used for biting and cutting food into smaller pieces. Canines: Located next to the incisors, these pointed teeth are used for tearing and gripping food. Premolars: Situated behind the canines, premolars have a flat surface and are used for crushing and shredding food. Molars: These are the large, flat teeth at the back of your mouth that are designed for grinding and crushing food to prepare it for swallowing.

Q86. Which one is NOT an involuntary function:

• A. Breathing
• B. Pumping of blood
• C. Skeletal muscle movement✓
• D. Blinking of eyes

Explanation: Involuntary functions are those that occur without our conscious control.Skeletal muscle movement is not an involuntary function;it is voluntary/intentional.Blinking of eyes, heart-pumping of blood, and breathing are all involuntary.

Q87. The temperature that promotes the maximum activity of enzymes is referred to as _.

• A. Fixed temperature
• B. Optimum temperature✓
• C. Controlled temperature
• D. Active temperature

Explanation: Enzymes are proteins that speed up reactions by lowering activation energy. Their activity depends on temperature. A rise in temperature increases enzyme activity by raising kinetic energy, but very high temperatures break peptide bonds, denaturing the enzyme. Low temperatures slow or deactivate enzymes, while the optimum range (20–35 °C) ensures maximum activity. At temperatures above 45 °C, enzymes are destroyed, though low molecular weight enzymes are more heat stable.

Q88. Most of the enzyme reactions are_?

• A. Reversible✓
• B. Irreversible
• C. Condensation
• D. Oxidation

Explanation: Enzyme-catalyzed reactions are reversible. Enzymes facilitate both the forward and reverse reactions of a chemical equilibrium, and the direction in which the reaction proceeds depends on the concentrations of the reactants and products. Enzymes catalyze reactions by lowering the activation energy required for both the forward and reverse reactions. As a result, they can facilitate the conversion of substrates into products and, under different conditions, facilitate the conversion of products back into substrates.

Q89. The maximum number of electrons that an orbital can accommodate is/are:

• A. 0
• B. 1
• C. 2✓
• D. 3
• E. 4

Explanation: The maximum number of electrons in a single orbital is two. The maximum number of electrons an orbital can accommodate is 2. As in an orbital two electrons can never have the same values of all 4 quantum no.s according to Pauli’s exclusion principle. So to follow this rule, an orbital can accommodate 2 electrons only.

Q90. Which of the following is not a nucleophile?

• A. NH3
• B. OH
• C. CN-
• D. Br2✓

Explanation: Br₂ is not a nucleophile because:No Significant Negative Charge:Nucleophiles are electron-rich species that donate electrons.Br₂ is a neutral molecule with no formal negative charge, making it less likely to donate electrons.Weak Electron Donation Ability:Even though Br atoms have lone pairs, they are held tightly and not readily available for donation.Instead, Br₂ tends to act as an electrophile (electron acceptor), especially in reactions like electrophilic addition.Polarizability but No Strong Nucleophilic Character:Br₂ is a polarizable molecule, meaning it can momentarily develop dipoles, but this does not make it a nucleophile.In reactions, Br₂ often undergoes heterolytic cleavage, forming Br⁺ (electrophile) and Br⁻ (nucleophile), where only Br⁻ is nucleophile.

Q91. Purification of bauxite whose major impurity Is silica (SiO2) is carried out through:

• A. Baeyer’s Method
• B. Hall’s Method
• C. Serpek’s Method✓
• D. Contact Method
• E. Electrolytic Method

Explanation: Serpek's method is used for the purification of bauxite if it contains an excess amount of silica (SiO2). The powdered bauxite is mixed with carbon and heated up to 1800˚C and a current of nitrogen is passed, aluminum nitride is obtained. Silica is converted into silicon (Si).

Q92. Chlorine is manufactured commercially by the electrolysis of aqueous sodium chloride (brine). Which other products are made in this process?

• A. Hydrochloric acid and hydrogen
• B. Hydrogen and sodium
• C. Hydrogen and sodium hydroxide✓
• D. Sodium and sodium hydroxide
• E. Hydrochloric acid and sodium

Explanation: Gas extraction: Chlorine can be manufactured by the electrolysis of a sodium chloride solution (brine), whichis known as the Chlor Alkali process. The production of chlorine results in the co-products of caustic soda (sodium hydroxide, NaOH) and hydrogen gas (H2).

Q93. The crystals formed as a result of vander der Waals interactions are:

• A. Molecular crystals✓
• B. Covalent crystals
• C. Metallic crystals
• D. Ionic crystals
• E. None of these

Explanation: Molecular crystals have Vander Waal forces between them. Covalent crystals have strong covalent bonds between its structure. Ionic crystals are bound by ionic bonding. Metallic bonds are bound by strong electrostatic attraction between positively charged ions and electrons dispersed in the matrix.

Q94. Which factor does affect the equilibrium constant Kc for a reaction?

• A. Temperature✓
• B. Pressure
• C. Catalyst
• D. Initial concentrations

Explanation: Changing the temperature shifts the equilibrium position based on whether the reaction is endothermic (absorbs heat) or exothermic (releases heat), according to Le Chatelier's Principle.3 Since the ratio of products to reactants changes, the value of K must also change.

Q95. Nascent hydrogen used in the formation of methane is obtained from the reaction of:

• A. NaHCO3 with Zn
• B. HCl with Zn✓
• C. KOH with Zn
• D. H2O with Zn
• E. CH3I with Zn

Explanation: The correct option is the reaction of HCl with Zn. This reaction produces nascent hydrogen, which is a highly reactive form of hydrogen represented as [H]. This nascent hydrogen can then participate in further chemical reactions, such as the formation of methane. The balanced chemical reaction is: Zn + 2HCl → ZnCl2 + 2[H].Other options are incorrect because they do not involve reactions that produce nascent hydrogen. NaHCO3, KOH, H2O, and CH3I with Zn do not result in the generation of nascent hydrogen under typical conditions.

Q96. The general formula for an aldehyde is:

• A. R-OH
• B. R-COOH
• C. R-CO-R
• D. R-X
• E. R-CHO✓

Explanation: Aldehydes and ketones have a carbonyl group (C=O) as a functional group. A ketone has two alkyl or aryl groups attached to the carbonyl carbon (RCOR’). The simplest ketone is acetone, which has two methyl groups attached to the carbonyl carbon (CH3COCH3).An aldehyde is similar to a ketone, except that instead of two side groups connected to the carbonyl carbon, they have at least one hydrogen (RCOH or R-CHO). The simplest aldehyde is formaldehyde (HCOH), as it has two hydrogens connected to the carbonyl group. All other aldehydes have one hydrogen bonded to the carbonyl group, like the simple molecule acetaldehyde, which has one hydrogen and one methyl group (HCOCH3).The carbonyl carbon in both aldehydes and ketones is electrophilic, meaning that it has a dipole due to the electronegativity of the attached oxygen atom. This makes the carbonyl carbon an ideal target for nucleophiles in a nucleophilic addition reaction. During this reaction, the nucleophile, or electron donor, attacks the carbonyl to form the tetrahedral intermediate. The negatively charged oxygen accepts a hydrogen ion to form a hydroxyl group.Typically, nucleophiles possess a negative charge or lone pair on a heteroatom, which can take several forms (OH-, RO-, CN-, R3C-, RNH2, ROH). For primary amines (RNH2), the reaction does not stop at the formation of the tetrahedral intermediate with a hydroxyl group. Rather, an elimination reaction occurs that produces a double-bonded carbon and nitrogen functional group known as an imine. Understanding the reactions that aldehydes and ketones can undergo provides a way to differentiate between these similar organic compounds.

Q97. Which of the following statements about H2S is false:

• A. It is a covalent compound
• B. It is a gas with a bad smell
• C. It is a strong reducing agent
• D. It is a molecule which is non linear
• E. It is a weak base in water✓

Explanation: H2S is a weak acid, donating two hydrogen ions in neutralization reactions, forming HS- and S-2 ions, not a weak base. Hence option E is the correct answer.H2S is a covalent compound with a rotten egg smell. It is a strong reducing agent with a bent (non-linear) geometry.

Q98. Benzene can be prepared from:

• A. From Petroleum
• B. From Coal
• C. From Acetylene
• D. From Phenol
• E. All of these✓

Explanation: The correct answer is that benzene can be prepared from all the mentioned sources. Petroleum: Benzene is obtained through catalytic reforming and steam cracking of naphtha, which are standard industrial processes for hydrocarbon refinement. Coal: During the carbonization of coal, benzene is one of the volatile compounds distilled from coal tar. Acetylene: Acetylene undergoes cyclic polymerization at high temperatures, forming benzene as a result. Phenol: Reduction of phenol using zinc dust is another chemical method to synthesize benzene, with zinc oxide as a byproduct. Thus, each method demonstrates a valid approach to benzene production.

Q99. Primary Alcohol is produced by reactions of Grignard's reagent with _ followed by hydrolysis in an acidic medium.

• A. Carbon dioxide
• B. Formaldehyde✓
• C. Acetaldehyde
• D. Ketone
• E. Methyl chloride

Explanation: The Grignard Reaction involves the addition of an organomagnesium halide (Grignard reagent) to carbonyl compounds. When Grignard reagents react with formaldehyde, a primary alcohol is produced upon hydrolysis in an acidic medium. Formaldehyde is unique as it is the simplest aldehyde, thus allowing the formation of a primary alcohol. Other aldehydes and ketones lead to secondary and tertiary alcohols, respectively. Carbon dioxide reacts with Grignard reagents to form carboxylic acids, not alcohols, and methyl chloride does not react to form an alcohol.

Q100. Diamond and Graphite

• A. are isotopes
• B. are isomers
• C. are allotropes✓
• D. have the same structure
• E. are equally hard

Explanation: Diamond and Graphite are allotropes of carbon. The term allotrope refers to one or more physical forms of a chemical element that occurs in the same physical state. Allotropes may show differences in chemical and physical properties.

Q101. Transition elements have coloured compounds because:

• A. Their bond energy is low
• B. They easily absorb energy
• C. Splitting of the five degenerate d-orbitals take place✓
• D. The d-orbitals are very close to p-orbitals
• E. Degenerate p-orbitals are present

Explanation: The reason why transition metals, in particular, are colorful is that they have unfilled or half-filled d orbitals. The Crystal Field Theory explains the splitting of the d orbital, which splits the d orbital into a higher and lower orbital.

Q102. In a double-bonded carbon atom (C=C)

• A. Hybridization occurs between the s-orbital and one p-orbital
• B. Hybridization occurs between the s-orbital and two p-orbitals✓
• C. Hybridization occurs between the s-orbital and three p-orbitals
• D. No hybridization occurs between the s-and p-orbitals
• E. Hybridization occurs between two s-orbitals and one p-orbital

Explanation: Since there is a double bond formed between two carbon atoms, this implies that the hybridization is sp2, and sp2 hybridization involves one s and two p orbitals.One bond=sp3Two bonds=sp2Three bonds=sp

Q103. The radii of the second orbit of the hydrogen atom calculated from Bohr's model is:

• A. 0.529 Å
• B. 4.8 Å
• C. 2.116 Å✓
• D. 3.4 Å
• E. 1 Å

Explanation: In Bohr's model, the radius of the nth orbit of a hydrogen atom is given by the formula rn = 0.529 x n²/Z Å, where n is the principal quantum number and Z is the atomic number. For hydrogen, Z = 1. For the second orbit (n=2), the radius is calculated as:r2 = 0.529 x 2²/1 = 0.529 x 4 = 2.116 Å.Therefore, the correct answer is 2.116 Å. The other options are incorrect because they either represent the radius of a different orbit (e.g., 0.529 Å for n=1) or are arbitrary values that do not match the calculation for n=2.

Q104. The series limit for the Balmer series of hydrogen spectrum occurs at 3664 A°. Calculate Ionization energy of hydrogen atom.

• A. 21.7 x 10-19 J
• B. 6.626 x 10-34 J
• C. 5.425 x 10-19 J✓
• D. 3664 x 10-10 J
• E. 3 x 108 J

Explanation: The Balmer emission lines correspond to transitions down to the level for which n=2. Given series is the Balmer series, so n1=2 and n2=∞ λ=3664A° Change in ionisation energy= Einfinity−E2= −E2 -E2 =-hc/λ -E2=6.626×10-34 ×3×10⁸/(3664x10-10) -E2 =−5.42×10−19 J so option C is the only correct option.

Q105. The amount of energy released by absorbing an electron in the valence shell is:

• A. Ionization Energy
• B. Electron Affinity✓
• C. Electronegativity
• D. Atomic Radius
• E. Atomization Energy

Explanation: Electron Affinity is the correct answer because it is defined as the amount of energy released when an electron is added to a neutral atom to form an anion. This process is exothermic for most elements, meaning energy is released.Ionization Energy is incorrect because it involves removing an electron, not adding one, and thus requires energy. Electronegativity is a measure of an atom's ability to attract electrons in a bond and does not directly involve energy release upon electron addition. Atomic Radius is a measurement of size and has no direct correlation with energy release. Atomization Energy pertains to breaking molecules into atoms, not adding electrons to individual atoms.

Q106. When an element exists in more than one crystalline form, the phenomenon is termed as:

• A. Isomorphism
• B. Allotropy✓
• C. Isomerism
• D. Anisotropy
• E. Enthalpy

Explanation: Allotropy is the correct answer because it describes the ability of an element to exist in multiple forms or structures in the same physical state, such as carbon which can be found as diamond, graphite, and graphene.Isomorphism is incorrect as it refers to different substances with the same crystal structure. Isomerism is about different structural arrangements in organic compounds, not crystalline forms. Anisotropy deals with directional properties and not multiple forms of an element. Enthalpy involves thermodynamic measurements, not crystalline structures.

Q107. What is the chemical formula for plaster of Paris?

• A. CuSO4·5H2O
• B. 2CaSO4·2H2O
• C. (CaSO4)⪽H2O✓
• D. MgSO4·7H2O
• E. Na2SO4·H2O

Explanation: The correct formula for plaster of Paris is (CaSO4)⪽H2O, which can also be represented as CaSO4·½H2O. It is created by heating gypsum to 120-180°C, resulting in a hemihydrate form of calcium sulfate. This compound is widely used in construction, art, and medical applications. The other options represent different chemical compounds that are unrelated to plaster of Paris.

Q108. Linear combination of atomic orbitals (LCAO) results in the formation of:

• A. Sigma bond
• B. Pi bond
• C. Bonding molecular orbitals only
• D. Bonding and antibonding molecular orbitals✓
• E. All of these options

Explanation: According to Molecular Orbital Theory (MOT), two atomic orbitals overlap resulting in the formation of molecular orbitals. Number of atomic orbitals overlapping together is equal to the molecular orbital formed. The two atomic orbital thus formed by LCAO (linear combination of atomic orbital) in the same phase or in the different phase are known as Bonding Molecular Orbital (BMO) and Antibonding Molecular Orbitals (ABMO) respectively.

Q109. 950 torr corresponds to:

• A. 3.5 atm
• B. 1 atm
• C. 3 atm
• D. 1.25 atm✓
• E. 2.25 atm

Explanation: 1 atm = 760 torr To convert torr into atm Value of torr is divided by 760 950/760 = 12.5.

Q110. The chemical properties of Sulphuric Acid is/are:

• A. Acidic properties
• B. Oxidizing properties
• C. Dehydrating properties
• D. Sulfonating properties
• E. All of these✓

Explanation: Sulfuric acid is a multi-functional chemical with a range of properties:Acidic properties: As a strong acid, sulfuric acid dissociates completely in water, releasing H+ ions, which are responsible for its acidic nature.Oxidizing properties: In redox reactions, sulfuric acid can act as an oxidizing agent, accepting electrons from other substances.Dehydrating properties: Sulfuric acid can remove water from other compounds, a process evident in its interactions with organic materials like carbohydrates.Sulfonating properties: Its ability to add sulfonate groups to organic compounds is crucial for producing sulfonated derivatives.Therefore, the correct answer is All of these, as sulfuric acid exhibits all these chemical properties. Each of the individual options represents just one aspect of its chemical behavior.

Q111. The electronic configuration of iron is:

• A. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d5
• B. 1s2, 2s2, 2p6, 3s2, 3p6, 4s1, 3d5
• C. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d6✓
• D. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d3
• E. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d2

Explanation: The electronic configuration of iron (Fe) with 26 electrons is: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d6. This follows the Aufbau principle, where electrons fill orbitals starting from the lowest energy level. The 4s subshell is filled before the 3d subshell. Options A, B, D, and E account for fewer electrons than iron's 26, each missing one or more electrons in their configuration.

Q112. The chemical name of the baking soda is:

• A. Sodium carbonate
• B. Sodium bicarbonate✓
• C. Sodium chloride
• D. Sodium hydroxide
• E. Both B and C

Explanation: The correct answer is Sodium bicarbonate. Sodium bicarbonate, also known as baking soda, is a chemical compound used primarily as a leavening agent in baking. It reacts with acids to produce carbon dioxide gas, which causes dough to rise. The other options are incorrect: sodium carbonate is used in cleaning and water softening, sodium chloride is table salt, and sodium hydroxide is a caustic substance used in cleaning and manufacturing.

Q113. Which of the following acids is used for etching glass?

• A. Hydrochloric Acid
• B. Nitric Acid
• C. Hydrofluoric Acid✓
• D. Sulphuric Acid
• E. Acetic Acid

Explanation: Hydrofluoric Acid (HF) is used for etching glass because it reacts with silicon dioxide (SiO2), the main component of glass, to form gaseous silicon tetrafluoride (SiF4) and water. This reaction effectively removes material from the glass surface, creating an etched pattern. The other acids listed, such as hydrochloric, nitric, sulphuric, and acetic acids, do not react with silicon dioxide and therefore cannot etch glass.

Q114. Non-stoichiometric compounds are formed by:

• A. Only alkali metals
• B. Only transition elements✓
• C. Only noble gases
• D. None of the above

Explanation: Non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having elemental composition whose proportions cannot be represented by a ratio of small natural numbers.

Q115. Which of the following statements are correct about noble gases?

• A. They belong to 18th group of the modern periodic table.✓
• B. Except Rn, all the remaining noble gases are present in the air.
• C. These elements belong to 17th group in the IUPAC system.
• D. These are highly reactive elements.
• E. None of the above

Explanation: Noble gases are elements located in the 18th group of the modern periodic table. This group is characterized by elements having a full valence electron shell, which makes them highly stable and largely unreactive. Therefore, Option A is the correct statement about noble gases. Options B, C, and D are incorrect because they misstate either the presence of noble gases in the air, their group number, or their reactivity. Option E is incorrect because Option A is indeed correct.

Q116. Magnesium oxide is used in the making of the lining of blast furnaces. It is extracted from seawater as follows. Aqueous calcium hydroxide is added to seawater. Ca(OH)2 (aq) + MgCl2 (aq) + Mg(OH)2(s) + CaCl2 (aq)The magnesium hydroxide is then filtered off and roasted. Which of the following comparisons between calcium and magnesium explains why magnesium hydroxide forms?

• A. Magnesium is less electropositive than calcium.
• B. Magnesium is lower than calcium in the reactivity series
• C. The enthalpy change of hydration for Mg2+ is less exothermic than for Ca2+
• D. The solubility product for Mg(OH)2 is lower than that for Ca(OH)2✓
• E. The magnitude of the lattice energy of Mg(OH)2 is less than that of Ca(OH)2

Explanation: The lesser the solubility product the more likely the precipitation will be. Magnesium hydroxide forms as a precipitate as compared to aqueous calcium hydroxide because the solubility product of Mg(OH)2 is lower than Ca(OH)2

Q117. Which one of the following formulae represents the organic compound formed when methylbenzene is heated under reflux with alkaline potassium manganate (VII) solution and the mixture then acidified?

• A. A
• B. B
• C. C
• D. D
• E. E✓

Explanation: Explanation is given below.

Q118. The false statement about lithium is:

• A. It is softer than other alkali metals✓
• B. It is least reactive
• C. It possesses higher melting and boiling points
• D. It forms chloride which is soluble in alcohol

Explanation: Lithium is actually harder than the other alkali metals (it can even scratch glass), while the others are very soft. So the statement “It is softer than other alkali metals” is false.

Q119. The raindrop acquires a spherical shape and ink spread over blotting paper due to:

• A. Surface tension✓
• B. Adhesive forces
• C. Viscosity
• D. Polarity
• E. Latent heat of vaporization

Explanation: A raindrop falling through the atmosphere forms a roughly spherical structure due to the surface tension of water. This surface tension is the “skin” of a body of water that makes the molecules stick together. The cause is the weak hydrogen bonds that occur between water molecules.

Q120. Sigma bond is formed by:

• A. Transferring the electrons
• B. Head-on overlapping of atomic orbitals✓
• C. Mutual but unequal sharing of electrons
• D. Parallel overlapping of atomic orbitals
• E. All of these options

Explanation: The sigma bond, the strongest type of covalent bond, is formed by the head-on overlapping of atomic orbitals. This overlap allows for maximum electron density between the two bonding nuclei, resulting in a stable bond. In contrast, ionic bonds are formed by the transfer of electrons (Option A), polar covalent bonds arise from mutual but unequal sharing of electrons (Option C), and pi bonds result from the parallel overlapping of atomic orbitals (Option D). Thus, Option B is the only correct description for sigma bond formation.

Q121. The heat of a reaction can be calculated by using:

• A. Joule's Law
• B. Ohm's Law
• C. Hess's Law✓
• D. Faraday's Law
• E. Boyle's Law

Explanation: Hess' law states that the change of enthalpy in a chemical reaction (i.e. the heat of reaction at constant pressure) is independent of the pathway between the initial and final states. In other words, if a chemical change takes place by several different routes, the overall enthalpy change is the same, regardless of the route by which the chemical change occurs (provided the initial and final conditions are the same). Hess’s law allows the enthalpy change (ΔH) for a reaction to be calculated even when it cannot be measured directly.

Q122. Hydrides which are prepared by passing hydrogen gas over hot alkali metals or alkaline earth metals are called:

• A. Covalent hydrides
• B. Ionic hydrides✓
• C. Complex hydrides
• D. Metallic hydrides
• E. Polymeric hydrides

Explanation: The correct answer is Ionic hydrides. Ionic hydrides are formed when hydrogen gas is passed over hot alkali or alkaline earth metals (except Be and Mg). In this reaction, the metal donates electrons to hydrogen, resulting in a compound with ionic properties. These hydrides are typically white crystalline solids that react with water to release hydrogen gas.Covalent hydrides involve electron sharing with non-metals, which is not the case here. Complex hydrides involve more complex combinations of elements and are not formed by the simple interaction described. Metallic hydrides involve transition metals and are formed by hydrogen absorption into metal lattices, not applicable here. Polymeric hydrides involve hydrogen bonding in networks, not relevant to this reaction.

Q123. A child's balloon has a volume 3.80 dm3, when the temperature is 35°C. If the balloon is put in a refrigerator and cooled to 5°C, the approximate volume of the balloon is (assume pressure inside the balloon is equal to atmospheric pressure):

• A. 3.00 dm3
• B. 3.43 dm3✓
• C. 3.08 dm3
• D. 3.25 dm3
• E. 0.54 dm3

Explanation: To solve this, we apply Charles's Law, which states that at constant pressure, the volume of a gas is directly proportional to its temperature in Kelvin. Start by converting the given temperatures from Celsius to Kelvin: T1 = 35°C + 273 = 308 K and T2 = 5°C + 273 = 278 K. Using the formula V1/T1 = V2/T2, we have:3.80 dm3 / 308 K = V2 / 278 K.Solving for V2 gives:V2 = (3.80 dm3 * 278 K) / 308 K = 3.43 dm3.Thus, the correct answer is 3.43 dm3. The other options either miscalculate the proportional change or do not apply Charles's Law correctly.

Q124. In a reaction:A+B < - > 2C When equilibrium was attained, the concentration was [A] = [B] = 4 moles/dm3[C]= 6 moles/dm3The equilibrium constant Kc of this reaction is:

• A. 1.25
• B. 2.25✓
• C. 3.25
• D. 2.75
• E. 3.75

Explanation: The equilibrium constant Kc is calculated using the expression: Kc = [C]² / [A][B]. For the reaction A + B < - > 2C, substitute the equilibrium concentrations: [C] = 6 moles/dm3, [A] = [B] = 4 moles/dm3. Thus, Kc = (6)² / (4)(4) = 36 / 16 = 2.25, confirming Option B as correct. Options A, C, D, and E result from errors in calculation or misinterpretation of the equilibrium constant formula.

Q125. Dissolution of ammonium nitrate in water is an endothermic process. Which of the following graphs shows how the temperature alters as the ammonium nitrate is added to water and then the solution is left at room temperature?

• A. Option A
• B. Option B✓
• C. Option C
• D. Option D

Explanation: Since it is an endothermic process it takes heat from the surrounding making the temperature fall below room temperature. The temperature then gradually then goes back to room temperature.

Q126. When 18 ×10-3 moles/dm3 of acetic acid react with 22×10-3 moles/dm3 of ethyl alcohol to form 40×10-3 moles/dm3 of ethyl acetate and 40×10-3 moles/dm3 of waterFind the value of equilibrium constant (Kc)

• A. 4.04✓
• B. 3.14
• C. 3.04
• D. 2.02
• E. 1.04

Explanation: Kc= Concentration of products / Concentration of Reactants. Reactants = acetic acid and ethyl alcohol Products = ethyl acetate and water Multiplication product of products (40 × 40 =1600) Divide by multiplication product of reactants (18× 22= 396) 1600/396= 4.04.

Q127. Sodium reacts with water more vigorously than lithium because it:

• A. Has a higher atomic weight
• B. Is more electronegative
• C. Is more electropositive✓
• D. Is a metal
• E. Has a high melting point

Explanation: Sodium reacts more vigorously with water than lithium primarily because sodium is more electropositive. Electropositivity increases as you move down a group in the periodic table, which means sodium, being below lithium, loses electrons more easily. This increased tendency to lose electrons results in a more vigorous reaction with water. Other factors such as atomic weight, electronegativity, and melting point are not the primary reasons for this difference in reactivity. All alkali metals including sodium and lithium are metals, so this characteristic is not a differentiating factor either.

Q128. From a mixture of CO2 and H2 gases, CO2 can be separated by passing the mixture through:

• A. Water at high temperature
• B. Water under high pressure✓
• C. Cold water
• D. Acidified water

Explanation: Carbon dioxide is separated from hydrogen by passing the mixture through the water under high pressure. When carbon dioxide is compressed into water at pressure, the CO2 gas dissolves into the liquid. When pressure is released, CO2 releases from the liquid as a gas in the form of gas bubbles. This process is also called carbonation and is the basis of many popular beverages. Since hydrogen will not dissolve in the water, the two gases will be effectively separated. Carbon dioxide will not dissolve in the forms of water given in all the remaining options, so separation can not occur, leaving only option B as the correct option.

Q129. Alkanes having five to seventeen carbon atoms per molecule are

• A. liquids✓
• B. solids
• C. gases
• D. semi solid wax

Explanation: Following are the state of alkanes with given carbon numbers: C1-C4=Gases C5-C17=Liquids C18+=Solids.

Q130. Which type of isomerism depends on the distribution of carbon atoms on each side of the functional group?

• A. Structural isomerism
• B. Functional isomerism
• C. Chain isomerism
• D. Metamerism✓

Explanation: This type of isomerism arises due to the presence of different alkyl chains on each side of the functional group.Structural isomer is a type of isomerism that uses the same formula but different structures. Functional isomerism is a type of isomerism in which two structures have the same formula but different functional groups. Chain isomers have the same molecular formula, but the way their carbon atoms are joined together differs from isomer to isomer.

Q131. 80% of the coal is used in _ ?

• A. Lime kiln✓
• B. Domestic purposes
• C. Fuel
• D. Motor bikes

Explanation: While coal has many uses, in some regions with specific industrial profiles, a significant portion (sometimes up to 80%) of the locally mined coal is used to fuel lime kilns for the production of bricks and cement.

Q132. Ethene is obtained by electrolyzing

• A. Potassium formate
• B. Potassium succinate✓
• C. Potassium acetate
• D. Potassium fumarate

Explanation: Option B is correct since Kolbe's electrolysis of potassium succinate gives CO2 and C2H4.Option A is incorrect since if Na(HCOO) is taken in a molten state then the electrolysis will provide Na+ and HCOO- ions and if the temp is high then H2 and CO2 will be released.Option C is incorrect since electrolysis of potassium acetate does not produce ethane.Option D is incorrect since electrolysis of potassium fumarate gives acetylene.

Q133. Sum of oxidation numbers of all the molecules in a neutral atom is

• A. Unity
• B. Negative
• C. 1
• D. 0✓

Explanation: Option D is correct since in a neutral atom the charge is zero. So if we equate all the oxidation numbers we get zero.Option A is incorrect since the charge on a neutral atom cannot be equal to unity.Option B is incorrect since the charge on a neutral atom cannot be negative.Option C is incorrect since the charge on a neutral atom cannot be 1.

Q134. A train is approaching a station at 90 km/h sounding a whistle of frequency 1000 Hz. What will be the apparent frequency heard by the listener sitting on the platform if the train moves away from the station at the same speed? (speed of sound= 340 m/s)

• A. 931.5 Hz✓
• B. 105.7 Hz
• C. 135.9 Hz
• D. 153.1 Hz
• E. 164.9 Hz

Explanation: To determine the apparent frequency heard by the listener, we use the Doppler effect formula:f' = f * (v + v_o) / (v + v_s)Here, f is the original frequency (1000 Hz), v is the speed of sound (340 m/s), v_o is the speed of the observer (0 m/s, as the observer is stationary), and v_s is the speed of the source (converted to 25 m/s from 90 km/h).Applying these values: f' = 1000 * (340 / (340 + 25)) = 931.5 Hz.The other options result from incorrect application of the Doppler effect formula, either due to incorrect speed conversions or misunderstanding the direction of motion, leading to incorrect frequency values.

Q135. 0.75 A current flows through an iron wire when a battery of 1.5 volts is connected across its ends. The length of the wire 5.0 m and its cross-sectional area is 2.5 x 10-7 m2. What is the resistivity of iron?

• A. 9.0 x 10-7 Ωm
• B. 7.0 x 10-7 Ωm
• C. 5.0 x 10-7 Ωm
• D. 3.0 x 10-7 Ωm
• E. 1.0 x 10-7 Ωm✓

Explanation: To solve this problem, start by using Ohm's law, V = IR, to find the resistance (R). Given V = 1.5 V and I = 0.75 A, R = V/I = 1.5 V / 0.75 A = 2 Ω.Next, use the formula for resistivity (resistivity = R × A / l), where A is the cross-sectional area (2.5 × 10-7 m2) and l is the length of the wire (5.0 m). Plugging in the values, resistivity = 2 Ω × (2.5 × 10-7 m2) / 5.0 m = 1.0 × 10-7 Ωm.Thus, the correct answer is 1.0 x 10-7 Ωm. The other options result from errors in applying the formulas or calculations.

Q136. In a certain circuit, a transistor has a collector current of 10mA and a base current of 40μA. What is the current gain of the transistor?

• A. 150
• B. 200
• C. 250✓
• D. 300
• E. 350

Explanation: To determine the current gain (β) of a transistor, use the formula: β = IC/IB. Here, the collector current (IC) is 10mA (10 × 10-3 A) and the base current (IB) is 40μA (40 × 10-6 A). Calculating gives:Current gain = (10 × 10-3 A) / (40 × 10-6 A) = 250.Therefore, the correct answer is Option C: 250. The other options (150, 200, 300, 350) do not match the calculated current gain of 250, making them incorrect.

Q137. When photons are incident on a metal, electrons are emitted. The process is called:

• A. Photoelectric effect✓
• B. Pair production
• C. X-ray production
• D. Gamma ray production
• E. Radioactive capture

Explanation: Photoelectric effect, a phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation. The effect is often defined as the ejection of electrons from a metal plate when light falls on it.

Q138. A bomb is dropped from an airplane moving horizontally with a speed of 200 km/h. If the air resistance is negligible, the bomb will reach the ground in 5 s, the altitude of the plane approximately is: (g = 9.8 m/s2)

• A. 50 m
• B. 75 m
• C. 122.5 m✓
• D. 250 m
• E. 300 m

Explanation: Data:u = t = 5 sec v = 200km/hr Solution: h = ut + 1/2gt2h = 1/2 x 9.8(5)2h = 1/2 * 245= 122.5Hence, option C is correct. The correct approach involves utilizing the equation of motion for free fall to calculate the vertical distance accurately. Option A underestimates, Option B does not consider the full effect of gravity, Option D overestimates, and Option E significantly overestimates the altitude due to misinterpretation of time and acceleration relationships.

Q139. The total outward flux over any closed hypothetical surface called _ is equal to the total charge enclosed divided by ε irrespective of how the charge is distributed.

• A. Coulomb surface
• B. Gaussian surface✓
• C. Ohm surface
• D. Faraday surface

Explanation: Gauss's law states that the total electric flux through a closed surface, also known as a Gaussian surface, is equal to the total charge enclosed by the surface divided by the permittivity of the medium (ε). This law helps in calculating electric fields around charge distributions with symmetry. The other terms, 'Coulomb surface', 'Ohm surface', and 'Faraday surface', do not apply to this context. Coulomb is related to charge, Ohm to resistance, and Faraday to electromagnetic induction, none of which define such a surface for Gauss's law.

Q140. When we measure the nuclear masses and compare them with the masses of the constituent nucleus in free states, the mass of the nucleus is always less than the mass of the constituent nucleons. The difference in mass is known as:

• A. Mass Defect✓
• B. Mass Value
• C. Mass Disorder
• D. Mass Energy
• E. Mass Nucleus

Explanation: The correct answer is Mass Defect. When nucleons (protons and neutrons) bind together to form a nucleus, some mass is converted into binding energy, leading to a total mass that is less than the sum of the individual nucleons' masses. This difference is the mass defect, which is a measure of the nuclear binding energy that holds the nucleus together.Mass Value refers to a general measurement of mass, not specific to nuclear physics.Mass Disorder is a medical term unrelated to nuclear physics.Mass Energy relates to Einstein's mass-energy equivalence principle, which is a broader concept not directly explaining the mass defect.Mass Nucleus is simply the total mass of protons and neutrons without accounting for the difference due to binding energy.

Q141. are very high-energy electromagnetic radiations of the extremely short wavelength emitted from the nuclei of radioactive atoms originating from the high energy transitions of the nucleons in the nuclei.

• A. Alpha rays
• B. Beta rays
• C. Gamma rays✓
• D. Electromagnetic rays
• E. Ultraviolet rays

Explanation: Gamma rays are the correct answer because they are high-energy electromagnetic radiations of extremely short wavelength emitted from the nuclei of radioactive atoms. They originate from the high-energy transitions of nucleons in the nuclei during radioactive decay. Unlike alpha and beta particles, which are particles, gamma rays are pure energy and highly penetrating. They are widely used in medical treatments, industrial applications, and scientific research, but they can pose significant health risks if exposure is not properly managed. The other options, including alpha and beta rays, involve particle emissions, and ultraviolet rays are not emitted from nuclear decay.

Q142. A 100 kg golf ball is moving to the right with a velocity of 20 m/s. It makes a head on collision with an 8 kg steel ball, initially at rest. The two balls get stuck together. What will the velocity of these two balls after collision?

• A. 14.3 m/s
• B. 17.5 m/s
• C. 18.5 m/s✓
• D. 19.7 m/s
• E. 20.0 m/s

Explanation: To solve this problem, apply the conservation of momentum principle which states that total initial momentum equals total final momentum in the absence of external forces. Before the collision, the golf ball (100 kg) moves with 20 m/s, and the steel ball (8 kg) is at rest. The initial momentum is calculated as:Initial Momentum = m1v1 + m2v2 = 100 kg × 20 m/s + 8 kg × 0 m/s = 2000 kg·m/s.After the collision, the two balls stick together, so their combined mass is 108 kg. Let the final velocity be u2. The equation becomes:2000 kg·m/s = (100 kg + 8 kg) × u2Solving for u2 gives:u2 = 2000 kg·m/s / 108 kg = 18.5 m/s.Thus, option C is correct. The other options incorrectly calculate the velocity by either misunderstanding the mass involved or misapplying the momentum conservation equation.

Q143. A row of 25 decorative lights, connected in series, is connected to a main transformer. When the supply is switched on, the lights do not work. The owner uses a voltmeter to test the circuit. When the voltmeter is connected across the third bulb in the row, a reading of zero is obtained. Which of the following cannot be the only fault in the circuit?

• A. The filament of one of the other bulbs has broken
• B. The filament of the third bulb has broken.✓
• C. The fuse in the mains transformer has blown.
• D. There is a break in the wire from the supply to the transformer.

Explanation: When a filament of a bulb in a series circuit is broken, it creates an open circuit causing the voltage to be maximum across that bulb. In this case, the third bulb's broken filament would result in a high voltage reading, not zero. The correct answer is that the filament of the third bulb has broken. This creates an open circuit, leading to the absence of current flow and hence zero voltage. The other options are incorrect because they do not explain the observed zero voltage across the third bulb.

Q144. Which unit expresses work per unit charge?

• A. Hertz
• B. Watt
• C. Joule
• D. Volt✓
• E. Half-life

Explanation: The correct answer is Volt. A volt measures the electrical potential difference and is defined as the work done per unit charge, expressed as 1V = 1J/1C. This means that one volt is equivalent to one joule of work done per one coulomb of charge. The other options are incorrect because:Hertz measures frequency, not related to work or charge.Watt measures power, defined as work per unit time, not charge.Joule is a unit of energy or work, not per unit charge.Half-life is a concept related to radioactive decay, not applicable to work or charge.

Q145. Physics is an experimental science which depends heavily on:

• A. Objective observations only
• B. Measurement of natural phenomena only
• C. Study of chemical solutions
• D. Both objective observations and measurement of natural phenomena✓

Explanation: Physics is an experimental science that fundamentally relies on both objective observations and the measurement of natural phenomena. These components work together to allow scientists to formulate hypotheses, conduct experiments, and establish scientific laws and theories. Option D is correct because it encompasses both necessary components. In contrast, Option A and Option B, while important individually, do not provide the comprehensive approach needed for successful scientific inquiry in physics. Option C is incorrect as it pertains more to chemistry than to physics.

Q146. How much energy is dissipated as heat in 20 s by a 100 Ω resistor that carries a current of 0.5 A?

• A. 50 J
• B. 100 J
• C. 250 J
• D. 500 J✓
• E. 1,000 J

Explanation: To determine the energy dissipated as heat in a resistor, use the formula: H = I²Rt. For this question, I = 0.5 A, R = 100 Ω, and t = 20 s. Applying these values: H = (0.5)² × 100 × 20 = 500 J, confirming that Option D is correct. Other options result from either incorrect squaring of the current, misapplication of the formula, or arithmetic errors.

Q147. A 10 nanofarad (10 x 10-9 F) parallel plate capacitor holds a charge of magnitude 50 µC on each plate.If the plates are separated by a distance of 0.885mm, what is the area of each plate?

• A. 1.0 m2✓
• B. 3.0 m2
• C. 5.5 m2
• D. 7.5 m2

Explanation: To find the area of each plate, we use the formula for the capacitance of a parallel plate capacitor: C = ε0 * (A/d), where C is the capacitance, ε0 is the permittivity of free space (approximately 8.85 x 10-12 F/m), A is the area of the plates, and d is the distance between the plates. Given C = 10 x 10-9 F and d = 0.885 x 10-3 m, we rearrange the formula to solve for A: A = (C * d) / ε0. Plugging in the values gives A = (10 x 10-9 F * 0.885 x 10-3 m) / 8.85 x 10-12 F/m = 1.0 m2. Thus, Option A is correct. The other options provide areas that are either too large or too small when calculated properly with the given values.

Q148. What will be the gravitational force of attraction between two balls each weighing 5 kg when placed at a distance of 0.33 m apart. (G = 6.673 x 10-11 Nm2/kg2 )

• A. 9.1 x 10-8 N
• B. 7.1 x 10-8 N
• C. 6.1 x 10-8 N
• D. 3.5 x 10-8 N
• E. 1.5 x 10-8 N✓

Explanation: To find the gravitational force of attraction between the two balls, use Newton's Law of Universal Gravitation: FG = G * (m1 * m2) / r2.Given values:m1 = 5 kgm2 = 5 kgr = 0.33 mG = 6.673 x 10-11 Nm2/kg2Substitute these into the formula:FG = 6.673 x 10-11 * (5 * 5) / (0.33)2Calculate:FG = 1.5 x 10-8 NTherefore, the correct answer is 1.5 x 10-8 N, which matches Option E.Other options result from errors in calculation, such as incorrect squaring of distance or arithmetic mistakes.

Q149. Calculate the final kinetic energy when a shop keeper pushes a fruit crate, initially at rest, towards another shopkeeper by exerting a constant horizontal force F of magnitude 5N through a distance of 1 meter.

• A. 2 J
• B. 3 J
• C. 5 J✓
• D. 7 J
• E. 9 J

Explanation: To solve this problem, apply the work-energy principle, which states that the work done on an object is equal to the change in its kinetic energy. Since the crate starts from rest, the initial kinetic energy is 0. The work done W is calculated by multiplying the constant force F by the displacement d: W = F × d = 5 N × 1 m = 5 J. This work done becomes the final kinetic energy of the crate, thus the correct answer is 5 J. Other options are incorrect as they do not match the calculation F × d using the given values.

Q150. The resultant of two forces has magnitude of 20N. If one of the forces is of magnitude 20√3 N and makes an angle of 30o with the resultant then, the other forces must be of magnitude:

• A. 10√3 N
• B. 20 N✓
• C. 20√3 N
• D. 10 N
• E. 37 N

Explanation: Correct option is 'B'.

Q151. is also known as anti-electron.

• A. Photon
• B. Proton
• C. Positron✓
• D. Nucleon

Explanation: The positron, also known as the antielectron, is the correct answer because it is the antimatter counterpart of the electron, with +1 charge and annihilation upon collision with an electron. Photons have zero charge, protons have antiprotons as antiparticles, and nucleons are a collection of protons and neutrons, not the antiparticle of an electron.

Q152. Nucleus with an excess of neutrons may decay radioactivity with the emission of:

• A. a neutron
• B. a proton
• C. an electron✓
• D. a positron

Explanation: When an unstable atomic nucleus has an excess of neutrons, it may undergo β− decay, where a neutron is converted into a proton and electron. This is why the correct answer is the emission of an electron. The other options, such as emitting a neutron, proton, or positron, do not align with the known decay processes of nuclei with excess neutrons.

Q153. A stone dropped from a certain height can reach the ground in 5 seconds. It is stopped after 3 seconds of its fall and then allowed to fall again. Find the time taken by the stone to reach the ground for the remaining distance.

• A. 2 s
• B. 4 s✓
• C. 6 s
• D. 8 s
• E. 10 s

Explanation: The stone is initially dropped from a height and falls for 3 seconds before being stopped. During this time, it falls a certain distance which can be calculated using the equation of motion: s = ut + (1/2)gt², where u is the initial velocity (0 m/s), g is the acceleration due to gravity (9.8 m/s²), and t is 3 seconds.After being stopped, the stone falls the remaining distance, which is the difference between the total height and the distance fallen in the first 3 seconds. It takes 4 seconds to fall this remaining distance, calculated using the same equation of motion. Therefore, the correct answer is 4 seconds.The other options are incorrect because they either underestimate or overestimate the time required for the stone to fall the remaining distance.

Q154. In the photoelectric effect, a photon of energy hv is incident on the metal surface. The energy required to eject the valence electron from the surface of the metal is expressed as:

• A. Wave nature of the light
• B. Compton scattering
• C. Melting point of the metal
• D. Work function of the metal✓

Explanation: The answer to the question will be option d, which is the work function of the metal. Now the definition of the work function of the metal can be given by that it is the minimum amount of energy per photon that is needed to eject an electron, or we can see valence electron from the surface of the metal. ○Photon is incident on the metal surface, the energy of photon breaks the electron-nucleus interaction and thus an electron is emitted from the metal surface. Since some energy is required to break that interaction to emit the electron, the photoelectric effect takes place from the metal surface only if the energy of the photon is greater than the work function of that metal.Work function:- the minimum energy required to bring out free electrons from the metal surface is called the work function of that metal. It depends only on the nature of the metal.it is measured in electron volts (e.v.).Final answer;Hence that amount of energy is called a work function.Here, the Compton effect, also called Compton scattering, increases in wavelength of X-rays and other energetic electromagnetic radiations that have been elastically scattered by electrons so this option is incorrect.

Q155. A conductor of length L is moved across a magnetic field. Due to this activity, a potential difference appears across the ends of the conductor. This type of potential difference is termed as:

• A. Self Induction
• B. Mutual Induction
• C. Motional EMF✓
• D. Electrostatic potential

Explanation: The correct answer is Motional EMF. When a conductor of length L moves across a magnetic field B, a potential difference appears across its ends, which is termed as motional EMF. This is induced by the movement of the conductor through the magnetic field. Self Induction and Mutual Induction involve induction of voltage in coils due to changing currents and proximity to other coils, respectively. Electrostatic potential relates to the work energy needed to move electric charge in an electric field.

Q156. mλ=2dsin(θ) this relation is called as

• A. Coulomb’s Law
• B. Bragg’s Law✓
• C. Faraday’s Law
• D. Ohm’s Law
• E. Gravitational Law

Explanation: Coulomb’s Law: the force of attraction or repulsion between two charged bodies is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. It acts along the line joining the two charges considered to be point charges.Faraday’s Law: Faraday's law of electromagnetic induction, also known as Faraday's law, is the basic law of electromagnetism which helps us predict how a magnetic field would interact with an electric circuit to produce an electromotive force (EMF).Ohm’s law: Ohm's law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperatures remain constant.Gravitational law: Newton’s Law of Universal Gravitation states that every particle attracts every other particle in the universe with force directly proportional to the product of the masses and inversely proportional to the square of the distance between them

Q157. The potential difference between the terminals of a battery in an open circuit is 2.2 V. When it is connected across a resistance of 5.0 Ω, the potential falls to 1.8 V. What is the internal resistance of the battery?

• A. 9.11 Ω
• B. 2.11 Ω
• C. 3.11 Ω
• D. 1.11 Ω✓
• E. 0.11 Ω

Explanation: To find the internal resistance of the battery, we can use the formulas:1. The emf, E, is the open-circuit voltage: E = 2.2 V.2. When the battery is connected to a resistance of 5.0 Ω, the terminal voltage V = 1.8 V.Using Ohm's Law, V = IR, where I is the current flowing through the external resistance. Therefore, I = V/R = 1.8 V / 5.0 Ω = 0.36 A.The internal resistance, r, can be found using the formula E = V + Ir, so 2.2 V = 1.8 V + 0.36 A * r.Solving for r gives r = (2.2 V - 1.8 V) / 0.36 A = 1.11 Ω.The correct answer is 1.11 Ω.Other Options:Option A (9.11 Ω), Option B (2.11 Ω), Option C (3.11 Ω), and Option E (0.11 Ω) are incorrect as they result from miscalculations or misunderstandings of the relationship between emf, internal resistance, and external resistance.

Q158. A 20.0 cm wire carrying a current of 10.0 A is placed in a uniform magnetic field of 0.30 T. If the wire makes an angle of 40° with the direction of the magnetic field, find the magnitude of the force acting on the wire? ( sin 40° = 0.642)

• A. 2.71 N
• B. 0.39 N✓
• C. 6.61 N
• D. 7.61 N
• E. 9.91 N

Explanation: The force on a current-carrying conductor in a magnetic field is given by the formula: F = ILBsin(θ), where:I is the current (10.0 A)L is the length of the wire (0.20 m)B is the magnetic field strength (0.30 T)θ is the angle between the wire and the magnetic field (40°)Substituting the given values into the formula, we have:F = 10.0 A * 0.20 m * 0.30 T * sin(40°) = 0.39 NTherefore, the correct answer is 0.39 N. The other options are incorrect due to calculation errors, such as neglecting the sine function or using incorrect values for the variables.

Q159. A particle of mass 5 mg moves with a speed of 8 m/s. Calculate its de Broglie wavelength (h = 6.63 x 10-34 J s).

• A. 0.71 x 10-29 m
• B. 1.66 x 1029 m
• C. 1.66 x 10-29 m✓
• D. 3.77 x 10-29 m
• E. 5.71 x 10-29 m

Explanation: The correct de Broglie wavelength is calculated using the formula λ = h/(mv). The mass of the particle is given as 5 mg, which is converted to 5 x 10-6 kg. The speed is 8 m/s, and Planck's constant h is 6.63 x 10-34 J s. Plug these values into the formula:λ = 6.63 x 10-34 / (5 x 10-6 kg x 8 m/s) = 1.66 x 10-29 m.

Q160. X-rays are also known as:

• A. Rydberg rays
• B. Roentgen rays✓
• C. Ultraviolet rays
• D. Zig-zag rays
• E. Ruby rays

Explanation: The correct answer is Roentgen rays. X-rays were discovered by Wilhelm Conrad Roentgen in 1895, and in honour of his discovery, they are often called Roentgen rays. This discovery was pivotal in the development of diagnostic imaging in medicine. The other options are incorrect as they do not relate to the historical or scientific context of X-rays. Rydberg is associated with atomic spectra, ultraviolet rays are a different part of the electromagnetic spectrum, and 'zig-zag rays' and 'ruby rays' are not scientifically recognised terms related to X-rays.

Q161. Two bodies ‘x’ and ‘Y’ are attached to the ends of a string which passes over a pulley so that the two bodies hang vertically. If the mass of the body ‘x’ is 5 kg and that of body ‘Y’ is 4.8 kg. Find the acceleration?(g = 9.8 m/s^2)

• A. 0.2 m/s2✓
• B. 1.7 m/s2
• C. 3.7 m/s2
• D. 4.9 m/s2
• E. 9.1 m/s2

Explanation: The acceleration of the system can be found using Newton's second law. The net force on the system is the difference in weight of the two masses: F = (mx - my) * g. Here, mx = 5 kg and my = 4.8 kg, and g = 9.8 m/s2. Therefore, the net force F = (5 - 4.8) * 9.8 = 0.2 * 9.8 = 1.96 N. The total mass of the system is 5 + 4.8 = 9.8 kg. To find acceleration, use the formula a = F / (mx + my), which gives a = 1.96 / 9.8 = 0.2 m/s2. Thus, the correct answer is Option A: 0.2 m/s2. The other options do not correctly account for both masses or the net force in the system.

Q162. A fixed mass of gas in a thermally insulated container is compressed. After compression, the temperature of the gas will have:

• A. fallen, since more molecules bombarded the container and so they must be moving slower
• B. fallen, since more molecules collide more frequently with one another and so their average speed is lower
• C. remained constant if the compression is very slow
• D. risen, since doing work on the gas increases the kinetic energy of the molecules✓
• E. risen, since there are more intermolecular collisions and so more heat is produced by them

Explanation: When a gas in a thermally insulated container is compressed, work is done on the gas, and no heat is lost to the surroundings. This increases the internal energy of the gas, which is directly proportional to the temperature. The increased kinetic energy of the molecules results in a rise in temperature.

Q163. A sample of an ideal gas may: expand adiabatically or expand isothermally. The net flow of heat into the gas from the exterior is:

• A. Positive in each case
• B. Negative for I and positive for II
• C. Positive for I and negative for II
• D. Zero in each case
• E. Zero in I and positive for II✓

Explanation: An adiabatic process is a thermodynamic process that involves the transfer of energy without transfer of heat or mass to the surrounding that it is zero in the case of I. While isothermal processes are those in which the temperature change is zero, that only implies the temperature change is zero, not the heat energy change.

Q164. Four particles independently move at the same speed in a direction perpendicular to the same magnetic field. Which particle is deflected the most?

• A. a copper ion
• B. a helium nucleus
• C. an electron✓
• D. a proton

Explanation: The deflection of a particle depends upon its mass to charge ratio. Since the mass of electron is too less as compared to its charge so it possesses maximum deflection. The electron would divert the most, the proton next and afterward the three particles. The amount they redirect relies upon their ionic states.

Q165. A generator of e.m.f. 80 V has an internal resistance of 0.04 Ω. If its terminal voltage is 75 V, determine the current.

• A. 125 A✓
• B. 135 A
• C. 145 A
• D. 155 A
• E. 165 A

Explanation: To determine the current, use the formula I = (E - V) / r, where E is the electromotive force (80V), V is the terminal voltage (75V), and r is the internal resistance (0.04Ω). Substitute the values into the formula to get I = (80V - 75V) / 0.04Ω = 125A. Therefore, option A is correct. All other options result from incorrect calculations based on this formula.

Q166. A 1000 kg vehicle is turning around a corner at 10 m/s as it travels along an arc of a circle. If the radius of the circular path is 10 m, how large a force must be exerted by the pavement on the tires to hold the vehicle in the circular path?

• A. 1.0 x 10⁴ N✓
• B. 3.0 x 10⁴ N
• C. 5.0 x 10⁴ N
• D. 7.0 x 10⁴ N
• E. 9.0 x 10⁴ N

Explanation: Given: mass = 1000kgvelocity = 10m/s radius = 10 mFind: F(centripetal force)=? Formula:F= mv²/r F= 1000×10²/10F= 10000F = 1×10⁴N

Q167. Kelvin is the unit of thermodynamic temperature, which is _ of the thermodynamic temperature of the triple point of water.

• A. 1/100.6
• B. 1/273.16✓
• C. 1/32.6
• D. 1/241.6
• E. 1/115.7

Explanation: The Kelvin scale is defined by the International System of Units (SI) such that one Kelvin is exactly 1/273.16 of the thermodynamic temperature of the triple point of water. This precise definition ensures that the Kelvin scale is an absolute temperature scale with absolute zero as its null point, where all molecular motion ceases. The correct answer is 1/273.16, as this is the standard definition. Other options like 1/100.6, 1/32.6, 1/241.6, and 1/115.7 are incorrect because they do not correspond to this established definition.

Q168. The circuit diagram shows a network of resistors each of resistance R. What is the effective resistance between the points X and Y?

• A. 2R/7
• B. R/2
• C. 5R/8✓
• D. 2R/3
• E. 3R/4

Explanation: Top two resistors placed in series have resistance, R+R=2R1 /R=1 /R+1 /2R=>1/R=3 /2R=> R=2/3*R (for combination two series with one parallel,on topmost side of diagram)1 /R=1 /R+1 /2R=>1/R=3 /2R=> R=2/3*R (for combination two series with one parallel,on topmost side ofdiagram)⅔ R+R=>(5/3)*R (for upper branch), which is in parallel with R of lower branch1 /R=3 /5R+R=>1/R=8 /5R=> R=5/8R,HENCE C is the correct option

Q169. A/An _ is that in which the momentum of the system as well as the kinetic energy of the system before and after the collision is conserved i.e. remains the same.

• A. Elastic collision✓
• B. Inelastic collision
• C. Conserved collision
• D. Direct collision

Explanation: An elastic collision is one where both momentum and kinetic energy of the system are conserved, meaning they remain the same before and after the collision. Inelastic collisions conserve momentum but lose some kinetic energy to other forms of energy. The term conserved collision lacks specificity and does not indicate which quantities are conserved. Direct collisions describe the nature of the impact rather than conservation laws.

Q170. A particle moves from position r= 3i+2j-6k to r= 14i+13j+9k under the action of a Force F= 8i+2j+6k. Find the work done by the force:

• A. 50 units
• B. 75 units
• C. 125 units
• D. 155 units
• E. 200 units✓

Explanation: Work done = force×displacement Given data:F=8i+2j+6k N Now displacement, d=(14i+13j+9k) — (3i+2j-6k)d=(14–3)i+(13–2)j+(9-[-6])k d=11i+11j+15k Now, W=F×d W= (8i+2j+6k) × (11i+11j+15k) W=(11×8)+(2×11)+(6×15)W=88+22+90 W=200J

Q171. The internal energy of the system decreases in an adiabatic process. Which of the following must be true regarding this process?

• A. Heat flows out of the system
• B. Work is done by the system✓
• C. Work is done by the surroundings
• D. The potential energy of the system is changing

Explanation: According to the first law of thermodynamics, Q = ΔU + W, where Q is the heat added to the system, ΔU is the change in internal energy, and W is the work done by the system. In an adiabatic process, Q = 0, so the equation simplifies to ΔU = -W. This means that if the internal energy decreases, W must be positive, indicating that work is done by the system on the surroundings. Thus, the correct answer is that work is done by the system. The other options are incorrect because they either suggest heat transfer (which does not occur in an adiabatic process) or involve potential energy, which is not directly related to the described process.

Q172. Look at this series 80, 10, 70, 15, 60. What number should come next?

• A. 20✓
• B. 25
• C. 30
• D. 50

Explanation: The series begins with 80, from which 10 is subtracted to get 70. Adding 5 to 70 yields 15, subtracting 10 from 15 results in 60. Following this alternating pattern, adding 5 to 60 gives 20, making Option A (20) the correct choice. Option B (25) mistakenly applies continuous addition, Option C (30) incorrectly adds 10, and Option D (50) repeats a subtraction step when addition is required.

Q173. Find the odd one.

• A. Mother
• B. Sister
• C. Maid✓
• D. Aunt

Explanation: The correct answer is Maid. In this question, mother, sister, and aunt are all directly related to an individual by blood, signifying familial connections. The maid, however, is a domestic worker with no blood or familial ties, making her distinct from the other options. Each incorrect option (Mother, Sister, Aunt) represents a family member, which excludes them from being the odd one out.

Q174. STATEMENT:I. An interior minister has been found as the owner of assets more than the stated income.II. The prime minister has ordered all the ministers to unveil their assets.

• A. Statement I is the cause and statement II is its effect
• B. Statement II is the cause and statement I is its effect✓
• C. Both statements I and II are independent causes
• D. Both statements I and II are the effects of independent cause

Explanation: The correct answer is Option B: Statement II is the cause and statement I is its effect.Analysis of the sequence of events shows that the prime minister's order for ministers to disclose their assets directly led to the discovery of the interior minister's unreported assets. This cause-and-effect relationship is supported by the context provided in the statements.Option A is incorrect because the prime minister's order is the catalyst for the subsequent discovery of the interior minister's assets, making Statement II the cause.Option C is incorrect as it fails to recognize the cause-and-effect relationship between the two statements, overlooking the context of the situation.Option D is also incorrect because it suggests that both statements are effects of an independent cause, which does not align with the information provided.

Q175. Statement 1: The life today is too fast, demanding and full of variety in all aspects which at times leads to stressful situations.Statement 2: Number of suicide cases among teenagers is on increase. Select the correct option:

• A. Statement I is the cause and II is its effect.✓
• B. Statement II is the cause and statement I is its effect.
• C. Both the statements I and II are independent causes.
• D. Both the statements I and II are effects of independent causes.

Explanation: Statement I describes a lifestyle that can lead to stress, which is a known factor contributing to mental health issues such as depression and anxiety. These issues can increase the risk of suicide, particularly among vulnerable groups like teenagers. Therefore, Statement I can be seen as a cause leading to the effect described in Statement II. The other options fail to recognize this causal relationship between the two statements.

Q176. If ‘-’ means ‘+’, ‘+’ means ‘-’, ‘*’ means ‘÷’ and ‘÷’ means ‘*’ then which of the following will be the correct equation?

• A. 10 + 5 - 14 ÷ 10 * 15 = 158
• B. 30 + 5 + 14 - 10 * 15 = 122
• C. 30 - 5 + 14 ÷ 10 * 15 = 162
• D. 30 * 5 - 4 ÷ 10 + 15 = 31✓
• E. None of these

Explanation: Your equation is:10 + 5 - 14 ÷ 10 * 15 = 158First, replace the symbols:+ → -- → +÷ → ** → ÷Thus, the equation becomes:10 - 5 + 14 * 10 ÷ 15Now, solve step-by-step following BODMAS:Multiplication and Division first:14 * 10 = 140140 ÷ 15 ≈ 9.333...Now the equation becomes:10 - 5 + 9.333...Left to right (Addition/Subtraction):10 - 5 = 55 + 9.333... = 14.333...Thus:Final result: 14.333..

Q177. Find the missing number in the series: 2, 6, 12, 20, 30, 42, 56, ?

• A. 61
• B. 64
• C. 72✓
• D. 70

Explanation: The series is generated by the product of consecutive integers: 1×2, 2×3, 3×4, 4×5, 5×6, 6×7, 7×8. The next term in the pattern is 8 × 9 = 72.

Q178. Each problem consists of three statements. Based on the first two statements, the third statement may be true, false, or uncertain.Class A has a higher enrollment than Class B.Class C has a lower enrollment than Class B.Class A has a lower enrollment than Class C.If the first two statements are true, the third statement is

• A. True
• B. False✓
• C. Uncertain
• D. None of these

Explanation: To solve this problem, we start by analyzing the relationships given: Class A has a higher enrollment than Class B, and Class C has a lower enrollment than Class B. This implies that Class A has the highest enrollment among the three. The third statement claims that Class A has a lower enrollment than Class C, which contradicts the derived relationship. Therefore, the third statement is false. Option B correctly identifies this inconsistency, while the other options misinterpret or overlook the logical deduction from the given statements.

Q179. Pick the odd word out:

• A. Just
• B. Fair
• C. Equitable
• D. Baised✓

Explanation: The correct answer is Biased. The words 'Just', 'Fair', and 'Equitable' all represent characteristics of honesty and impartiality. 'Biased', on the other hand, indicates partiality and a lack of fairness, making it the odd one out. While the first three options suggest a sense of equality and justice, 'Biased' denotes favoritism and prejudice, which are contrary to the common theme of the other words.

Q180. Each problem consists of three statements. Based on the first two statements, the third statement may be true, false, or uncertain.Tanya is older than Eric.Cliff is older than Tanya.Eric is older than Cliff.If the first two statements are true, the third statement is:

• A. True
• B. False✓
• C. Uncertain
• D. None of these

Explanation: Given the statements: 'Tanya is older than Eric' and 'Cliff is older than Tanya', we can deduce that Cliff is the oldest, followed by Tanya, and then Eric. Therefore, the statement 'Eric is older than Cliff' is false as it contradicts the established order of ages. The correct answer is option B: False. Options A and C are incorrect as the statements provide enough information to conclude that the third statement is false, not true or uncertain. Option D is incorrect as option B is the correct choice.