Sindh Mdcat Mock Paper 4 — Solved Past Paper with Answers

Q1. Complete the sentences by choosing the most appropriate word, from the given lettered choices below:Somebody has not turned the tap _.

• A. Of
• B. Off✓
• C. Over
• D. In
• E. At

Explanation: Option B is correct because 'off' is used to indicate disconnection or stopping the operation of something, such as turning off a tap to stop the water flow.

Q2. Read the following passage to answer the given question;The fact that we were all as safe as kittens under a cook-stove did not, however, assuage in the least the fine despair and the grotesque desperation which seized upon the residents of the East Side when the cry spread like a grass fire that the dam had given way. Some of the most dignified, staid, cynical, and clear thinking men in town abandoned their wives, stenographers, homes, and offices and ran east. There are few alarms in the world more terrifying than 'The dam has broken!' There are few persons capable of stopping to reason when that clarion cry strikes upon their ears, even persons who live in towns no nearer than five hundred miles to a dam.The phrase "spread like a grass fire" means

• A. Rapid spread✓
• B. Firefighting
• C. Grass growth
• D. Dreadful sight
• E. Hidden news

Explanation: The phrase 'spread like a grass fire' is a metaphor used to describe something that spreads very quickly and widely, akin to how a fire can rapidly move through dry grass. In the passage, it illustrates the swift dissemination of panic among the residents.

Q3. Find the errorMr. Ahmed is to old to work now; he depends upon his son.

• A. Mr.
• B. To✓
• C. Work now
• D. Depends
• E. No error

Explanation: This is incorrect because "to" is a preposition or part of an infinitive verb (e.g., "to go," "to read"), but the sentence requires "too," which means "excessively" or "more than needed." The phrase should be "too old to work", meaning Mr. Ahmed is excessively old to continue working. Using "to" instead of "too" changes the meaning and creates a grammatical error.

Q4. Complete the sentences by choosing the most appropriate option, from the given lettered choices (A to D) below each. The milkman _ many bottles of milk to our school every day.

• A. delivers✓
• B. has deliver
• C. have deliver
• D. delivering

Explanation: The sentence 'The milkman _ many bottles of milk to our school every day.' requires a verb that agrees with the singular subject 'milkman' and fits the context of a habitual action. The correct answer is 'delivers' because it is in the present simple tense, suitable for describing routine actions. 'Has deliver' and 'have deliver' are incorrect as they misuse the verb forms for the present perfect tense, and 'delivering' is incorrect because it is a participle used in continuous tenses.

Q5. Choose the correct spelling:

• A. Amatuer
• B. Amature
• C. Amateur✓
• D. Ameteur

Explanation: The correct spelling is Amateur, which refers to someone who engages in a pursuit for pleasure rather than for financial benefit. This word is borrowed from French, where the ending 'ateur' is a common suffix. The other options, such as 'Amatuer', 'Amature', and 'Ameteur', are incorrect as they either reorder the vowels incorrectly or alter the word's structure, diverging from the original spelling.

Q6. 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.

Q7. Identify the word or phrase that needs to be changed for the sentence to be correct.The guests broke a dozen glass at the party.

• A. The guests
• B. Broke
• C. Glass✓
• D. At
• E. No Error

Explanation: The given sentence is an example of a simple sentence. A simple sentence contains a subject and a verb, and it may also have an object and modifiers. However, it contains only one independent clause.The word "glass" requires a change to the plural form "glasses." The word or phrase that needs to be changed for the sentence to be correct is "glass"" (should be changed to "glasses").

Q8. Choose the word most similar in meaning to the capitalized one.SHABBY:

• A. Organized
• B. Untidy✓
• C. Reluctant
• D. Sensible

Explanation: Shabby (adjective) means (of things) in poor condition especially because of age or use. It also means (of person) dressed in clothes that are old and worn.

Q9. Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters:SUPREMACY

• A. Excellency
• B. Sovereignty
• C. Inferiority✓
• D. Influence

Explanation: Supremacy (noun) is defined as the state or condition of being superior to all others in authority, power, or status.

Q10. A condition of failure of kidney to form urine is called:

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

Explanation: Anuria is the medical term for the complete cessation of urine production by the kidneys, often resulting from severe kidney damage or failure. In contrast, 'Deamination' refers to a metabolic process unrelated to kidney function. 'Uremia' describes a condition where waste products accumulate in the blood due to impaired kidney function, but does not specifically indicate the absence of urine production. Therefore, Anuria is the correct choice as it directly addresses the failure to form urine.

Q11. A decrease in blood pressure/volume will not cause the release of:

• A. Atrial natriuretic factor✓
• B. Aldosterone
• C. ADH
• D. Renin

Explanation: The correct answer is Atrial natriuretic factor (ANF). ANF is secreted by the atria of the heart in response to increased blood volume and pressure, not a decrease. It works to reduce blood volume and pressure by promoting sodium excretion and decreasing the release of aldosterone. On the other hand, Aldosterone, ADH, and Renin are all released in response to a decrease in blood pressure or volume. Aldosterone increases sodium reabsorption, ADH reduces water excretion, and renin triggers the renin-angiotensin-aldosterone system to increase blood pressure.

Q12. A biological defense of our body with greater speed and effectiveness is called:

• A. Infestation
• B. Disinfestation
• C. Immunity✓
• D. Antisepsis

Explanation: The correct answer is Immunity. Immunity is a key biological defense that enables the body to swiftly and effectively combat pathogens through its immune system, reducing susceptibility to infections. Unlike infestation, which describes unwanted organisms invading an area, and disinfestation, which involves removing such organisms, immunity is about internal defense mechanisms. Antisepsis, meanwhile, is an external method to prevent infection, not an internal immune function.

Q13. Vaccine is available for all, EXCEPT:

• A. Hepatitis B
• B. Tuberculosis
• C. Malaria✓
• D. Polio

Explanation: Malaria does not currently have a widely available vaccine, unlike Hepatitis B, Tuberculosis, and Polio, which all have established vaccines used globally. The Hepatitis B vaccine is essential for preventing the Hepatitis B virus, the BCG vaccine protects against tuberculosis, and the polio vaccine prevents poliomyelitis. Ongoing research targets malaria vaccine development, but it is not yet universally implemented.

Q14. _ is the kind of immunity which is obtained as a result of an infection:

• A. Natural Active Immunity✓
• B. Artificial Active Immunity
• C. Natural Passive Immunity
• D. Artificial Passive Immunity

Explanation: Natural active immunity is acquired when an individual's immune system responds to an actual infection, leading to the production of antibodies and memory cells that provide long-term protection. This is distinct from artificial active immunity, which involves vaccination, and passive immunity forms, which rely on the transfer of antibodies rather than the immune system's active response.

Q15. Cellular totipotency was demonstrated by:

• A. Theodore Schwann
• B. A.V. Leeuwenhoek
• C. F.C. Steward✓
• D. Robert Hooke

Explanation: Professor F.C. Steward made significant contributions to the field of plant tissue culture. In 1958, he demonstrated calular totipotency by regenerating a whole plant from a single carrot cell, which established the potential for cells to develop into completa organisms.

Q16. At high altitude, the RBCs in the human blood will :

• A. Increase in number✓
• B. Decrease in number
• C. Increase in size
• D. Decrease in size

Explanation: This statement is accurate. At high altitudes, where the oxygen concentration in the air is lower, the body's response includes an increase in the number of red blood cells (RBCs). This is known as polycythemia. It's an adaptive mechanism to improve oxygen-carrying capacity, helping to transport more oxygen to body tissues.

Q17. When scientists make an animal superior by view of genotype, introducing some foreign genes in it, is called :

• A. Immunization
• B. Genetic engineering✓
• C. Tissue culture
• D. Biotechnology

Explanation: Genetic engineering is the correct answer because it directly involves altering an organism's genetic material to improve or change its traits. This can include the introduction of foreign genes to make an animal superior by enhancing its genotype. Immunization, on the other hand, is about disease prevention and does not involve genetic modification. Tissue culture is a method of growing cells and is primarily used for plants without altering their genetic makeup. Biotechnology is a broad term that includes genetic engineering but is not exclusively about modifying an organism's genes to enhance its traits.

Q18. Any foreign substance often a protein which stimulates the formation of antibodies is called:

• A. Antigen✓
• B. Antibody
• C. Prion
• D. Virion

Explanation: The correct answer is 'Antigen'. Antigens are foreign substances, often proteins, that stimulate the immune system to produce antibodies to fight off potential threats. Antibodies, on the other hand, are proteins made by the immune system in response to antigens; they do not initiate the immune response. Prions and virions are infectious agents but do not directly stimulate antibody production as antigens do.

Q19. What is vital capacity of our lungs?

• A. Inspiratory reserve volume plus expiratory reserve volume
• B. Total lung capacity minus residual volume✓
• C. Inspiratory reserve volume plus tidal volume
• D. Total lung capacity minus expiratory reserve volume

Explanation: All options are explained below:A. Inspiratory reserve volume plus expiratory reserve volume:The vital capacity of the lungs is calculated by adding the inspiratory reserve volume (the maximum additional air that can be inhaled after a normal inhalation) to the expiratory reserve volume (the maximum additional air that can be exhaled after a normal exhalation). This option is accurate and describes the correct method for calculating vital capacity.B. Total lung capacity minus residual volume (Correct Option):: The vital capacity of the lungs is indeed calculated as the difference between the total lung capacity (the maximum amount of air the lungs can hold) and the residual volume (the volume of air that always remains in the lungs, even after forceful exhalation). This option is accurate, and it describes the correct calculation for vital capacity.C. Inspiratory reserve volume plus tidal volume: This option is not accurate. The vital capacity is not calculated by adding the inspiratory reserve volume to the tidal volume (the amount of air normally inhaled and exhaled during quiet breathing). Vital capacity includes the inspiratory and expiratory reserve volumes.D. Total lung capacity minus expiratory reserve volume: This option is not accurate. Subtracting the expiratory reserve volume from the total lung capacity does not yield the vital capacity. The vital capacity includes both the inspiratory and expiratory reserve volumes.Summary: The correct option for calculating the vital capacity of the lungs is B, which involves subtracting the residual volume from the total lung capacity. This method accurately represents the maximum amount of air that can be forcefully exhaled after a maximum inhalation. Option A, although accurate, combines the inspiratory and expiratory reserve volumes to calculate vital capacity. Options C and D do not correctly describe the calculation of vital capacity.

Q20. Just as the_filter the lymph, the_filters blood.

• A. Lymph nodes, Spleen✓
• B. Spleen, Lymph nodes
• C. Lymph nodes, Lymph nodes
• D. Spleen, Spleen

Explanation: The correct answer is that lymph nodes filter lymph, while the spleen filters blood. Lymph nodes are integral to the lymphatic system, which is essential for immune function and the removal of foreign particles from lymphatic fluid. In contrast, the spleen is a crucial organ within the circulatory system that filters blood, recycles old red blood cells, and serves as a site for immune cell activity. The other options are incorrect because they either mix up the functions or inaccurately assign roles to these organs.

Q21. In case of uremia, to remove nitrogenous wastes, particularly the urea, the blood of the patient is treated through:

• A. Centrifugation
• B. Lithotripsy
• C. Transfusion
• D. Dialysis✓

Explanation: Dialysis is the correct answer as it is a medical procedure used to remove waste products like urea from the blood when the kidneys are not functioning properly. It serves as an artificial replacement for lost kidney function. The other options are incorrect because:Centrifugation is not used in medical treatment for waste removal from blood.Lithotripsy targets kidney stones, not blood purification.Transfusion replenishes blood components but does not remove metabolic wastes.

Q22. Asthma may be attributed to:

• A. Inflammation of the trachea
• B. Accumulation of fluid in the lungs
• C. Bacterial infection of the lungs
• D. Allergic reaction of the mast cells in the lungs✓

Explanation: Asthma is often associated with allergic reactions where allergens trigger the activation of mast cells in the lungs. These cells release chemicals like histamines, leading to airway inflammation and bronchoconstriction, which are hallmarks of asthma.

Q23. Blood analysis of a patient reveals an unusually high quantity of carboxyhaemoglobin content. Which of the following conclusions is most likely to be correct? The patient has been inhaling polluted air containing unusually high content of:

• A. Oxygen
• B. Chloroform
• C. Carbon dioxide
• D. Carbon monoxide✓

Explanation: Carboxyhaemoglobin is formed when hemoglobin binds to carbon monoxide (CO), a process that occurs when polluted air containing high levels of carbon monoxide is inhaled. This can occur due to the incomplete combustion of fuels.

Q24. Lymph nodes get their supply from:

• A. Many efferent lymph vessels
• B. Single efferent lymph vessels
• C. Many afferent lymph vessels✓
• D. Single afferent lymph vessels

Explanation: Lymph nodes are an integral part of the lymphatic system, acting as filters for foreign particles and cancer cells. They receive lymph from multiple afferent lymph vessels, which allows the lymph to be filtered before it exits through a single efferent lymph vessel. This setup facilitates efficient filtration and immune response. The incorrect options either confuse the roles of afferent and efferent vessels or incorrectly quantify the number of vessels involved.

Q25. The heart is enclosed in a double membranous sac called:

• A. Thoracic cavity
• B. Chest cavity
• C. Pericardium✓
• D. Pleural cavity

Explanation: The correct answer is the pericardium, which is a double-walled sac specifically enveloping the heart and the roots of the major blood vessels. It contains pericardial fluid that minimizes friction during heart activity. The thoracic and chest cavities are broader spaces that include the heart and lungs but do not specifically enclose the heart. The pleural cavity is related to the lungs and does not involve the heart.

Q26. Third step in PCR technique is:

• A. Heating DNA for one minute to denature
• B. Cooling for two minutes and adding primer
• C. Addition of DNA polymerase and waiting for 1.5 minutes✓
• D. Recycling

Explanation: The PCR process consists of three main steps: denaturation, annealing, and extension. During the third step, known as extension, DNA polymerase is added to synthesize the new DNA strands, and this step takes about 1.5 minutes. The other options describe either the first step (denaturation), the second step (annealing), or a non-specific term (recycling) that does not correspond to a particular step in the PCR cycle.

Q27. Which one of these is the possibility for most of us with regard to breathing, by making a conscious effort?

• A. One can consciously breathe in and out using only the diaphragm without moving the ribs✓
• B. It is possible to completely empty the lungs by forcefully exhaling all air
• C. You can exhale all air from the lungs without any residual volume
• D. Breathing out through the Eustachian tubes is possible by closing both the nose and mouth

Explanation: Conscious control can be exerted to use the diaphragm alone for breathing, a technique known as diaphragmatic breathing. This method is often employed in relaxation and meditation practices.

Q28. People who have migrated from the planes to a higher altitude area about six months back:

• A. Have an increased number of RBCs and their hemoglobin has a lower affinity for O2✓
• B. Are generally unfit for physical activities like football
• C. Experience altitude sickness with symptoms such as nausea and fatigue
• D. Maintain usual RBC count but have hemoglobin with a very high affinity for O2

Explanation: At higher altitudes, the body adapts to lower oxygen availability by producing more red blood cells (RBCs). This increases the oxygen-carrying capacity of the blood. Additionally, hemoglobin may decrease its affinity for oxygen to facilitate better oxygen delivery to tissues, which is crucial in a low-oxygen environment.

Q29. Approximately seventy percent of carbon­ dioxide absorbed by the blood will be transported to the lungs:

• A. As bicarbonate ions✓
• B. In the form of dissolved gas molecules
• C. By binding to R.B.C
• D. As carbamino haemoglobin.

Explanation: About 70% of CO₂ in the blood is carried to the lungs as bicarbonate ions (HCO₃⁻) formed when CO₂ reacts with water under the influence of the enzyme carbonic anhydrase in red blood cells.

Q30. 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.

Q31. Lungs are made up of air­filled sacs, the alveoli. They do not collapse even after forceful expiration because of

• A. Inspiratory reserve volume
• B. Tidal volume
• C. Expiratory reserve volume
• D. Residual volume✓

Explanation: Even after a forceful expiration, a certain amount of air always remains in the lungs. This is called residual volume. It prevents the alveoli from collapsing completely, ensuring continuous exchange of gases (O₂ and CO₂) between breaths.

Q32. Lungs do not collapse between breaths, and some air always remains in the lungs, which can never be expelled because:

• A. There is a negative pressure in the lungs
• B. There is a negative intrapleural pressure pulling at the lung walls✓
• C. There is a positive intrapleural pressure
• D. Pressure in the lungs is higher than atmospheric pressure

Explanation: Option B is correct.All options are explained below:a)There is a negative pressure in the lungs."This statement is not entirely accurate. Lungs don't naturally have a negative pressure, and they can't be filled with air if there is a consistent negative pressure. Lungs maintain a degree of positive pressure to keep them expanded.b) "There is a negative intrapleural pressure pulling at the lung walls": This option is correct. Between breaths, the lungs do not collapse due to the presence of a negative intrapleural pressure. Intrapleural pressure is the pressure in the pleural cavity, which surrounds the lungs. It is typically lower than atmospheric pressure, creating a "suction" effect that keeps the lungs inflated. This is a key mechanism for lung expansion and prevents lung collapse.c)"There is a positive intrapleural pressure": This statement is not accurate. A positive intrapleural pressure would not be conducive to maintaining lung expansion; it's the negative intrapleural pressure that plays a critical role in preventing lung collapse.d)"Pressure in the lungs is higher than the atmospheric pressure": This is not correct. The pressure in the lungs, during exhalation, is generally close to atmospheric pressure, but it's the intrapleural pressure that is negative, not the pressure in the lungs themselves.Summary: The correct answer is: "There is a negative intrapleural pressure pulling at the lung walls." The negative intrapleural pressure, which is lower than atmospheric pressure, keeps the lungs expanded by exerting a suction effect on the lung walls, preventing lung collapse between breaths.

Q33. An enzyme increases the speed of a reaction:

• A. By adding activation energy requirements.
• B. By lowering the activation energy requirements.✓
• C. By altering the equilibrium of the reaction.
• D. By changing the concentration of products.

Explanation: Enzymes serve as biological catalysts that increase the rate of chemical reactions by lowering the activation energy required for the reaction to proceed. Activation energy is the minimum amount of energy needed to initiate a reaction. By providing an alternative reaction pathway with a lower activation energy, enzymes allow reactions to occur more rapidly.Option A is incorrect because enzymes do not add to the activation energy requirements; they reduce them. Option C is incorrect because enzymes do not alter the equilibrium position of the reaction; they only accelerate the rate at which equilibrium is reached. Option D is incorrect because while enzymes affect the rate of reaction, they do not directly change the concentration of products.

Q34. The following reaction occurs in the human alimentary canal. What is the enzyme and the product?

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

Explanation: Amylase is an enzyme that plays a crucial role in the digestion of carbohydrates, specifically starch, in the alimentary canal (digestive system). The alimentary canal includes the mouth, where the digestion process begins, as well as the stomach, small intestine, and large intestine. Starch is a complex carbohydrate made up of long chains of glucose molecules. The digestion of starch begins in the mouth with the action of salivary amylase. Salivary amylase is produced by the salivary glands and released into the mouth along with saliva. Its primary function is to break down starch into simpler sugars, such as maltose and glucose.

Q35. Which of the following is NOT a difference that would allow one to distinguish between a prokaryotic and a eukaryotic cell? Presence or absence of the nucleus Presence or absence of the cell wall Membrane bound versus no membrane bound organelles

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

Explanation: Eukaryotic cells have nucleus and membrane-bound organelles, which is not the property of prokaryotes.The cell wall is not a distinguishing feature between prokaryotes or eukaryotes.

Q36. Some enzymes require the presence of a non protein molecule to behave catalytically. An enzyme devoid of this molecule is called a(n):

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

Explanation: Enzyme with a non-proteinous part is called Holoenzyme; without that non-proteinous part, it is called Apoenzyme.

Q37. Which type of protein structure contains the three dimensional structure?

• A. Primary
• B. Secondary
• C. Tertiary✓
• D. Quaternary

Explanation: The primary structure is a sequence of amino acids in the protein/polypeptide. The secondary structure is a 2D structure. The tertiary structure is a 3D structure. Quaternary structure is when two or more 3D structures join together.

Q38. 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.

Q39. Which part of the cell does glycolysis occur in?

• A. Mitochondrion
• B. Chloroplast
• C. Cytoplasm✓
• D. Nucleus
• E. Vacuole

Explanation: Glycolysis, the first stage of cellular respiration, occurs in the cytoplasm of the cell. It is a series of biochemical reactions that break down one molecule of glucose into two molecules of pyruvate. Unlike the subsequent stages of cellular respiration (such as the citric acid cycle and oxidative phosphorylation), glycolysis does not take place in the mitochondria. Instead, it occurs in the cytoplasm, which is the gel-like substance that fills the cell and surrounds the cellular organelles.

Q40. Which of the following is not a viral disease?

• A. AIDS
• B. Malaria✓
• C. Influenza
• D. Chickenpox

Explanation: Malaria is not a viral disease and is caused by the protozoan Plasmodium. All other options are viral infections that include AIDS caused by the HIV virus, influenza caused by the influenza virus, chickenpox caused by the varicella-zoster virus (VZV), and rabies caused by the rabies lyssavirus.

Q41. The diagram shows some of the organs of the human body. In which organs does the digestion of carbohydrates take place?

• A. P and Q
• B. P and R✓
• C. Q and R
• D. Q and S

Explanation: Digestion of carbohydrates takes place in the mouth (P) with the help of salivary amylase which converts starch to maltose. It also occurs in the intestine(R) with the help of pancreatic amylase, which yields disaccharides from starch by digesting the glycosidic bonds. The disaccharides produced (maltose, maltotriose, and α-dextrins) are all converted to glucose by brush border enzymes. Q is the stomach where protein digestion starts. S is the liver where digestion does not take place, although it does aid in digestion by producing bile and enzymes. So option B is correct (P & R)(Mouth and small intestine).

Q42. Which one of the following combinations of statements is true of saccharides in living organisms?

• A. Option A: Saccharides do not provide energy or form storage compounds.
• B. Option B: Saccharides serve none of the functions such as energy provision, storage, or structural support.
• C. Option C: Saccharides provide energy but do not serve as storage compounds.
• D. Option D: Saccharides are involved in ATP formation but not in structural support.
• E. Option E: Saccharides provide energy, form storage compounds, and offer structural support.✓

Explanation: The correct answer is Option E. Saccharides, or carbohydrates, have multiple essential roles in living organisms. They are vital for energy production as they are involved in ATP formation, serve as storage compounds like glycogen in animals and starch in plants, and provide structural support through cellulose in plant cell walls. The other options incorrectly deny one or more of these functions, which are fundamental characteristics of saccharides.

Q43. The following sequence of events occurs at the neuromuscular junction. nerve impulse -> release of V -> end plate potential -> W produced in muscle fibre -> X release from sarcoplasmic reticulum -> Formation of Y -> muscle contraction.Which one of the following shows the correct sequence from V -> Y?

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

Explanation: The correct sequence of events at the neuromuscular junction is as follows:Nerve impulse triggers the release of Acetylcholine (V) from the presynaptic neuron.Acetylcholine binds to receptors, generating an End Plate Potential, leading to an Action Potential (W) in the muscle fiber.The Action Potential triggers the release of Calcium ions (X) from the sarcoplasmic reticulum.Calcium ions bind to regulatory proteins, allowing the formation of Actomyosin (Y) cross-bridges, leading to muscle contraction.V = Acetylcholine, W = Action Potential, X = Calcium ions, Y = Actomyosin ✅ (Correct)

Q44. Which of the following is not secreted by thyroid gland?

• A. Thyroxin
• B. Triiodothyronine
• C. Calcitonin
• D. Glucagon✓

Explanation: The correct answer is Glucagon. Glucagon is secreted by the pancreas, not the thyroid gland. Its primary function is to increase blood glucose levels, which is crucial for maintaining energy balance in the body. On the other hand, Thyroxin (T4), Triiodothyronine (T3), and Calcitonin are all hormones secreted by the thyroid gland. Thyroxin and Triiodothyronine are involved in regulating metabolism, while Calcitonin helps control calcium levels in the blood.

Q45. Which of the following types and functions of the neuron is correct?

• A. Sensory neurons carry impulses from sensory receptors to the CNS; interneurons relay signals within the CNS; motor neurons transmit impulses from the CNS to muscles or glands✓
• B. Motor neurons carry sensory impulses to the CNS; interneurons transmit impulses to muscles; sensory neurons relay signals within the CNS
• C. Interneurons carry impulses from effectors to the CNS; sensory neurons transmit impulses from the CNS to interneurons; motor neurons pass signals within the CNS
• D. Sensory neurons transmit impulses from the CNS to effectors; motor neurons carry sensory information to the CNS; interneurons connect sensory to motor neurons outside the CNS

Explanation: Sensory neurons function to carry the sensory information to the CNS. Interneurons transfer impulses from sensory to motor neurons, remaining within the CNS. Motor neurons are neurons that transmit impulses fromthe CNS to the effectors.

Q46. Viruses can only survive and reproduce inside a:

• A. Animal cells
• B. Bacterial cells
• C. Living cells✓
• D. Non-living cells

Explanation: Option C is correct. Viruses are obligate intracellular parasites that can only reproduce inside living cells, whether plant, animal, or bacterial. They are not considered living organisms since they cannot replicate on their own or survive in non-living cells. Instead, they inject their genetic material into a host cell and use its machinery to produce new viruses, which then go on to infect other cells.

Q47. The genome of viruses is composed of

• A. DNA
• B. RNA
• C. Protein
• D. Both A and B✓

Explanation: Correct. Viruses can have either a DNA or RNA genome, depending on the type of virus. They do not have both at the same time, but this option correctly includes all possibilities.

Q48. Referring to sexual reproduction, humans are:

• A. Hermaphrodites
• B. Vivaparous✓
• C. Oviparous
• D. Self-fertilized

Explanation: The main difference between oviparous and viviparous animals is that oviparous animals do not undergo any embryonic development inside the mother whereas viviparous animals develop into young animals inside the mother. This means oviparous animals lay eggs. These eggs develop and hatch into young individuals.A hermaphrodite is an organism with both male and female genitalia. In sexually reproducing organisms, males have organs that produce male gametes, usually sperm. Sometimes the genders pair off equally, one male for one female. Other times, one male or female will breed with a large group of the other gender.

Q49. Scurvy is caused by deficiency of vitamin _.

• A. A
• B. B
• C. C✓
• D. D

Explanation: Scurvy is caused due to a deficiency of vitamin C (ascorbic acid). Vitamin C plays a crucial role in the synthesis of collagen, which is essential for the proper functioning of blood vessels, connective tissues, and wound healing. The deficiency of vitamin C leads to the breakdown of collagen, resulting in symptoms of scurvy such as fatigue, weakness, joint pain, and gum bleeding. However, deficiencies of vitamins A, B, and D do not result in scurvy. Vitamin A is essential for vision and immune function, vitamin B encompasses a group of vitamins involved in various aspects of metabolism and nervous system function, and vitamin D is crucial for calcium absorption and bone health. While deficiencies of these vitamins can cause other health issues, they do not directly contribute to the development of scurvy.

Q50. The optimum pH for the action of pepsin and salivary amylase is

• A. 3.5 and 7.7 respectively
• B. 1.8 and 6.8, respectively✓
• C. 6.8 and 7.4 respectively
• D. 1.8 and 7.4 respectively

Explanation: The stomach has a pH between 1.5 and 3.5 generally, and this is due to the cells in the stomach releasing hydrochloric acid, which is where pepsin is present, so it has a low optimum pH of around 2, so options A and C are incorrect. Saliva has a pH normal range of 6.2-7.6, with 6.7 being the average pH, which means salivary Amylase should have an optimum pH around the same range. Amylase has an optimal pH between 6.4 and 7.0.

Q51. The hormone labeled X in the diagram is often used in over-the-counter diagnostic tests to determine when ovulation has occurred. This hormone is:

• A. Estrogen
• B. Progesterone
• C. FSH
• D. LH✓

Explanation: The correct answer is LH, as it is the hormone whose surge triggers ovulation and is detected by ovulation prediction kits. Estrogen and progesterone play roles in preparing and maintaining the uterine lining, not in the detection of ovulation. FSH is involved in follicle development but not directly in ovulation prediction. Testosterone is a predominantly male hormone and irrelevant to this context.

Q52. Which of the following processes is the reverse of condensation?

• A. Hydrolysis✓
• B. Dehydration synthesis
• C. Polymerization
• D. Vapourization

Explanation: The correct answer is Hydrolysis because it involves breaking down molecules by adding water, which is the reverse of condensation reactions like dehydration synthesis. This is crucial in biological systems for breaking down complex molecules like proteins into amino acids. Dehydration synthesis involves removing water to form bonds, which is part of the condensation process itself. Polymerization is about forming large molecules from small units and can involve various types of reactions, not specifically the reverse of condensation. Vapourization is a physical change from liquid to gas, not related to the chemical processes described.

Q53. Ovulation is induced by _ hormone secreted by the pituitary gland.

• A. Follicle stimulating
• B. Estrogen
• C. Luteinizing hormone✓
• D. Progesterone

Explanation: Luteinizing hormone (LH), aids in egg maturation and provides the hormonal trigger to cause ovulation and the release of eggs from the ovary.

Q54. Many sarcomeres in series make up the length of a:

• A. Microtubules
• B. Myofibril✓
• C. Myosin filament
• D. M-line

Explanation: The subunits of a 'myofibril' are sarcomeres.

Q55. A pure breeding plant with the dominant phenotype of character P and the recessive phenotype of character Q was crossed with another pure breeding plant with the recessive phenotype of character P and the dominant phenotype of Q. The offspring of this cross were crossed with a double homozygous recessive for P and Q and the following results were obtained:22 were phenotypically dominant for P and recessive for Q5 were phenotypically dominant for both P and Q4 were phenotypically recessive for both P and Q24 were phenotypically recessive for P and dominant for QWhich one of the following types of Inheritance is illustrated by these results?

• A. Gene linkage of P and Q✓
• B. Independent segregation of P and Q
• C. Mendelian dihybrid Inheritance
• D. Multiple alleles
• E. Polygenic Inheritance

Explanation: When a pure breeding phenotypic dominant character P and recessive character Q is crossed with pure breeding recessive character P and dominant character Q, the cross is below:- PPqq X ppQQ will give PpQq. Now when this PpQq is crossed with recessive for both:- PpQq X ppqq will give PpQq ; Ppqq ; ppqq ; ppQq The ratio when there is a dihybrid cross between heterozygous character and homozygous recessive character is 9:3:3:1. However, the above ratio is not consistent with what it should be. This happens when there is a gene linkage between two characters

Q56. Flower color is controlled by a single pair of alleles. The allele for red flowers is dominant to the allele for white flowers. A plant homozygous for red flowers is crossed with a plant homozygous for white flowers. All the resulting plants have red flowers (F1 generation). When the F1 generation crosses with each other, 18 plants are obtained. 12 plants have red flowers and 6 have white flowers (F2 generation). What ratio is expected in the F2 generation and what ratio has been obtained?

• A. 3:1 expected, 2:1 obtained✓
• B. 2:1 expected, 3:1 obtained
• C. 1:1 expected, 3:1 obtained
• D. 1:1 expected, 2:1 obtained

Explanation: The correct answer is that the expected ratio in the F2 generation is 3:1, and the obtained ratio is 2:1. In a typical Mendelian monohybrid cross (Rr x Rr), the expected phenotypic ratio is 3:1, with three plants having the dominant phenotype (red flowers) for every one plant with the recessive phenotype (white flowers). The obtained ratio of 2:1 suggests a deviation from the expected, possibly due to a small sample size or experimental error. The other options incorrectly present the expected and obtained ratios.

Q57. Two animals are mated. One is homozygous dominant for one character and homozygous recessive for another. The other animal Is heterozygous for both characters. How many phenotypes are expected in the offspring of this cross?

• A. 1
• B. 2✓
• C. 3
• D. 4

Explanation: To understand and solve this, you can divide your thinking into two. For character 1. When genes are passed down to offspring, when the genes of this character pass down, the Dominant gene will always be present, so only one phenotype is possible from this character. For character 2. Three genotypes are possible, RR, Rr, and rr. RR and Rr are one phenotype and rr another. Total 2 So 2*1=2 total phenotypes

Q58. The diagram shows some similarities between golgi apparatus, mitochondria and suicide sacs. Which one is correct?

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

Explanation: Option D is the only option that makes sense. Suicide sacs are lysosomal enzymes that are membrane bound. Mitochondria and golgi apparatus are also membrane bounded organelles.

Q59. Mendel concluded that each organism has two hereditary factors for each trait, now called:

• A. Chromatids
• B. Alleles✓
• C. Chromosomes
• D. None of the above

Explanation: Pisum sativum has 14 chromosomes (2n = 14) arranged in 7 homologous pairs.

Q60. All of the following are reflex actions EXCEPT:

• A. Change in the size of the pupil in response to light
• B. Swallowing of the bolus✓
• C. Sudden jerky withdrawal of hand when pricked
• D. Knees jerk in response to a blow

Explanation: Reflex actions are involuntary and instantaneous responses to stimuli. The change in pupil size, jerky withdrawal of the hand, and knee jerk are all reflex actions because they occur automatically and without conscious thought. However, swallowing of the bolus, while it begins with a reflexive component, is primarily a voluntary action because it requires conscious control, especially after the initial trigger, making it not purely reflexive.

Q61. What happens during muscle contraction to the length of each myosin and actin filament?

• A. A band becomes short
• B. | band elongates
• C. There is no change in sarcomere
• D. Z- lines get close✓

Explanation: Option D is correct since the sarcomere shortens during muscle contraction. A sarcomere is a structure bound by two consecutive Z lines. So when the sarcomere shortens, the Z-lines come closer. Option A is incorrect since, during muscle contraction, the width of the A-band does not change. Option B is incorrect since the I-band shortens and does not elongate during muscle contraction. Option C is incorrect since the width of the sarcomere reduces during muscle contraction. The changes observed during muscle contraction are as follows :

Q62. Which of the following steps occurs immediately after the binding of Ca2+ with a troponin molecule during muscle contraction?

• A. Binding sites of actin get attached to the myosin head
• B. Troponin uncovers the actin binding sites
• C. Ca2+ goes back inside sarcoplasmic reticulum
• D. Tropomyosin gets removed from the binding sites of actin filaments✓

Explanation: Soon after the binding of Calcium ions, tropomyosin gets removed from the binding sites of actin filaments". It provides space for the myosin filament to attach to the actin filament for muscle contraction.

Q63. Blood circulating from the gut to the heart passes through the:

• A. Aorta
• B. Kidneys
• C. Liver✓
• D. Lungs

Explanation: The hepatic portal system carries nutrient-rich blood from the gut to the liver before it enters systemic circulation.

Q64. The diagram shows the inheritance of haemophilia in a family. What is the genotype of person 7?

• A. XH XH
• B. XH Y
• C. XH Xh✓
• D. Xh Xh
• E. Xh Y

Explanation: Haemophilia is a sex-linked recessive disorder. This means that if the father has the recessive allele (Xh), then he will have the disease. Since the brother of person 7 had haemophilia, this shows that the mother was a carrier of haemophlia and hence the daughter (person 7) can also be suspected to be a carrier of heamophilia, since one X chromosome is recieved by the daughter from the mother. The indication that one of the sons had haemophlia confirms that the mother was a carrier as they go the recessive allele from her.

Q65. Which features do animal cells share with plant cells?

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

Explanation: Mitochondria, cytoplasm and nucleus are found in both plant and animal cells. However, chloroplast is the organelle found in plant cells but lacking in animal cells.

Q66. Which statement about dominant and recessive alleles is not correct?

• A. A dominant characteristic is seen in the phenotype of a heterozygote.
• B. A homozygous genotype may be either dominant or recessive.
• C. Recessive phenotypes always have two recessive alleles.
• D. The phenotype of a homozygote is always dominant.✓

Explanation: Phenotype of a homozygote can be dominant or recessive both AA or aa. Hence statement D is incorrect and our answer.

Q67. In a laboratory, while working on a new species of fish, it is found that the fish has two varieties, red and brown. It was determined by another group of scientists in another laboratory that brown is a dominant color in this species. If we have brown fish with us in the laboratory, how can we determine whether they are homozygous or heterozygous for the trait?

• A. Breed this fish with a redfish and check F1 generation✓
• B. Breed this fish with a redfish and check F2 generation
• C. Breed this fish with a brown fish and check F1 generation
• D. Breed this fish with a brown fish and check F2 generation

Explanation: To find out whether the given species is homozygous or heterozygous we should breed it with species having a recessive phenotype and check the first (F1) generation. If even one of the offsprings from the F1 generation have a recessive phenotype that means our species was heterozygous or else homozygous.

Q68. Scapula is a:

• A. Tail bone
• B. Hip bone
• C. Skull bone
• D. Shoulder bone✓

Explanation: The scapula or shoulder blade is the bone that connects the clavicle to the humerus. The scapula forms the posterior of the shoulder girdle. It is a sturdy, flat, triangular bone. The scapula provides attachment to several groups of muscles.

Q69. Muscle contraction depends on:

• A. Nerve impulse
• B. Energy
• C. Calcium
• D. All of these options are correct✓

Explanation: Muscle contraction begins when the nervous system generates a signal. The signal, an impulse called an action potential, travels through a type of nerve cell called a motor neuron. The source of energy that is used to power the movement of contraction in working muscles is adenosine triphosphate (ATP). Ca2+ ions play an important role in muscle contraction by creating interactions between the proteins, myosin, and actin. The Ca2+ ions bind to the C component of the actin filament, which exposes the binding site for the myosin head to bind to, to stimulate a muscle contraction.

Q70. Cartilage is a form of:

• A. Cardiac tissue
• B. Connective tissue✓
• C. Epithelial tissue
• D. Nervous tissue

Explanation: Cartilage is a type of connective tissue that provides support, flexibility, and cushioning in joints, the rib cage, ear, nose, and trachea. It consists of chondrocytes embedded in a firm extracellular matrix. This is the correct answer.

Q71. If a cross-section of a sarcomere is seen, each myosin is surrounded by how many actin molecules?

• A. 5
• B. 6✓
• C. 7
• D. 8

Explanation: The correct answer is Option B: 6. In the structure of a sarcomere, each myosin filament is surrounded by six actin filaments, forming a hexagonal arrangement. This precise arrangement allows for efficient muscle contraction and gives skeletal muscle its characteristic striated appearance. Each actin filament is also surrounded by three myosin filaments, facilitating the sliding filament mechanism of muscle contraction. Options A, C, and D are incorrect because they do not reflect the actual structural arrangement of myosin and actin filaments within a sarcomere.

Q72. The massive accumulation of blood within a tissue is called:

• A. Hemorrhage
• B. Haematoma✓
• C. Hepatoma
• D. Haemocoel
• E. Haematemesis

Explanation: A hematoma is a localized collection of blood outside vessels, usually due to vessel injury.

Q73. The diagram represents two liquids, separated by a membrane through which osmosis can occurWhat movement of molecules will occur?

• A. Molecules of dissolved substance move from left to right
• B. Molecules of dissolved substance move from right to left
• C. Overall, water molecules move from left to right✓
• D. Overall, water molecules move from right to left
• E. None of the above

Explanation: Osmosis is the movement of water from a region of lower solute concentration (left side) to a region of higher solute concentration (right side) through a semi-permeable membrane. Since the right side has more dissolved substances, water moves from left to right to balance the concentration.

Q74. The system responsible for fighting the pathogens is:

• A. Muscular System
• B. Endocrine System
• C. Nervous System
• D. Immune System✓

Explanation: The immune system defends against infections using innate (nonspecific) and adaptive (specific) mechanisms.

Q75. Which row correctly shows the areas of the gas exchange system that contain cartilage, ciliated epithelium and goblet cells?

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

Explanation: It is a fact that bronchioles don't have cartilage, so options A and C are incorrect. Goblet cells are mucus secretory cells in the gas exchange system, and since alveoli don't contain mucus they have no need for goblet cells, so option B is also incorrect. This leaves option D which is the correct answer.

Q76. The disease night blindness is caused by deficiency of vitamin:

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

Explanation: Night blindness, or nyctalopia, is the inability to see in low light and is a symptom of an underlying eye condition, not a disease itself. It can be caused by conditions like cataracts, glaucoma, or retinal diseases, as well as genetic factors, injury, or nutritional deficiencies, such as a lack of Vitamin A.

Q77. When a color-blind male marries a normal female, what will be the chances of colorblindness in his grandsons, if his daughter is married to a normal male?

• A. 16%
• B. 25%
• C. 50%✓
• D. 100%

Explanation: The correct answer is 50%. When a color-blind male marries a normal female, all their daughters will be carriers of the color-blind gene because they inherit the X chromosome carrying the gene from their father. When one of these carrier daughters marries a normal male, each son has a 50% chance of inheriting the X chromosome carrying the color-blind gene, resulting in a 50% chance of being color-blind. The other options are incorrect because they do not correctly apply the rules of X-linked recessive inheritance.

Q78. The phenomenon in which the effect of one allele in a heterozygous genotype completely masks the effect of another is called

• A. Codominance
• B. Dominance
• C. Incomplete dominance
• D. Complete dominance✓

Explanation: In complete dominance, only one allele in the genotype is seen in the phenotype. In codominance, both alleles in the genotype are seen in the phenotype. In incomplete dominance, a mixture of the alleles in the genotype is seen in the phenotype.

Q79. Phenotypic ratio of monohybrid cross in producing F2 generation is:

• A. 3:1✓
• B. 9:3:3:1
• C. 1:1:2:1
• D. 1:1:1:1

Explanation: In the offspring of monohybrid crosses, or F2 generation, Mendel repeatedly observed a phenotype ratio of three plants with the dominant phenotype to one plant with the recessive phenotype (3:1) in the F2 generation.

Q80. One type of congenital heart defect is called atrial septal defect (ASD). Which of the following rows describes the effects of ASD on blood pressure and oxygenation?

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

Explanation: In ASD, blood moves from left to right atrium, increasing pulmonary artery pressure, decreasing systemic aorta pressure, and increasing oxygen saturation in pulmonary artery.

Q81. Dietary fibre passes through several structures after leaving the stomach. In which order do the dietary fibres pass through the structures?

• A. Duodenum -> Jejunum -> Ileum -> Rectum -> Colon
• B. Ileum -> Duodenum -> Colon -> Jejunum -> Rectum
• C. Ileum -> Duodenum -> Jejunum ->Rectum -> Colon
• D. Colon -> Duodenum -> Ileum -> Rectum -> Jejunum
• E. Duodenum -> Jejunum -> Ileum -> Colon -> Rectum✓

Explanation: The correct order for dietary fiber passing through the digestive system after leaving the stomach is: duodenum, jejunum, ileum, colon, and finally rectum. This sequence follows the natural progression from the small intestine, where digestion and absorption occur, to the large intestine, where water absorption and feces formation take place. Option E correctly lists this sequence. The other options fail to follow this order, either starting in the middle of the process or misplacing the positions of the colon and rectum.

Q82. Homozygous means:

• A. Alleles in an organism
• B. Two different alleles of a gene
• C. Having two identical genes
• D. Having two identical alleles of a gene✓

Explanation: Homozygous refers to an organism having two identical alleles for a specific gene, meaning both alleles are the same, whether they are dominant or recessive. This is in contrast to heterozygous, where two different alleles are present. Option D correctly captures this definition. Option A is too general as it only mentions alleles without specifying their sameness or difference. Option B describes a heterozygous state, which involves different alleles. Option C incorrectly uses the term 'genes' instead of 'alleles', which is a crucial distinction when discussing genotypes.

Q83. Which one of the following is Multiple allelic characters?

• A. Colour of flower in pea plant
• B. Blood group of the human being✓
• C. Shape of seed in pea plant
• D. Length of stem in pea plant

Explanation: Multiple alleles are the alternative forms of the same gene so they influence the same trait. An excellent example of multiple allele inheritance is human blood type. Blood type exists as four possible phenotypes: A, B, AB, & O. There are 3 alleles for the gene that determines blood type.

Q84. During which of the following levels of biological organization can natural selection occur?

• A. Gene
• B. Individual
• C. Group
• D. All of these✓

Explanation: h'Natural selection' is the process through which species adapt to their environments. It is the engine that drives evolution. Individuals in a population are naturally variable, meaning that they are all different in some ways. This variation means that some individuals have traits better suited to the environment than others.Group selection refers to the idea that natural selection sometimes acts on whole groups of organisms, favouring some groups over others, leading to the evolution of traits that are group-advantageous.'Natural selection' is the process through which species adapt to their environments. It is the engine that drives evolution. Individuals in a population are naturally variable, meaning that they are all different in some ways. This variation means that some individuals have traits better suited to the environment than others.Group selection refers to the idea that natural selection sometimes acts on whole groups of organisms, favouring some groups over others, leading to the evolution of traits that are group-advantageous.

Q85. What protein, present in sarcomeres, is responsible for the passive elasticity of muscle?

• A. Collagen
• B. Myosin
• C. Titin✓
• D. Actin and myosin

Explanation: Titin is a massive protein that spans the length of half of a sarcomere (from the Z-disc to the M-line) and allows for the passive elasticity of muscle.

Q86. In nostrils, the substance which moistens and keep the incoming air warm is called:

• A. Bronchi
• B. Mucous✓
• C. Pharynx duct
• D. Glottis

Explanation: When you inhale, the air is first conditioned in the nasal cavity so it reaches the lungs at an appropriate temperature and humidity and free of large particles. The nostrils and nasal cavity have hairs (vibrissae) that block large debris, and the convoluted nasal conchae produce turbulence so air contacts a large, well-vascularized mucous surface. Goblet cells and seromucous glands secrete mucus that humidifies the air and traps particles and microbes; enzymes and IgA in the mucus help neutralize pathogens. The dense capillary plexus in the nasal mucosa transfers heat to the inhaled air, warming it toward body temperature, and cilia move the mucus with trapped debris toward the pharynx to be cleared. Because of these combined features, mucus (from the nasal mucosa) is the primary substance in the nostrils that moistens and helps keep incoming air warm, protecting the delicate lower respiratory tract and optimizing conditions for gas exchange.

Q87. The bicep and tricep muscles are located in:

• A. Shank
• B. Upper arm✓
• C. Shoulder
• D. Lower jaw

Explanation: The biceps are located on the front of the upper arm and provide arm flexion, while the triceps are found on the back of the upper arm and are responsible for arm extension.

Q88. During Aristotle's time, it was thought that:

• A. Organisms ranged from simple to complex
• B. One type of organism gives rise to another type of organism
• C. Both A & B✓
• D. All living things were specially created by nature

Explanation: The correct answer is Both A & B. Aristotle recognized a natural order from simple to complex organisms, and while he did not propose a theory of evolution as understood today, the idea that one organism could give rise to another was present in ancient thought. Option D is incorrect as it suggests a creationist perspective not attributed to Aristotle.

Q89. Sperms are developed at what temperature?

• A. Lower than body temperature✓
• B. Body temperature
• C. Higher than body temperature
• D. All of these

Explanation: Sperm development (spermatogenesis) occurs at a temperature lower than body temperature. The testes are located outside the body in the scrotum, which helps maintain a slightly lower temperature conducive to spermatogenesis.

Q90. During inspiration, the area of the thoracic cavity will _.

• A. Contract
• B. Increase✓
• C. Decrease
• D. Damage

Explanation: During inspiration, the space inside the chest cavity is increased in two ways. Firstly, the muscles of ribs contract and elevate the ribs upwards and forwards and secondly, the muscles of diaphragm also contract and diaphragm becomes less domelike. This downward movement of the diaphragm and outward and upward movement of the ribs causes increase in the chest cavity and reduces pressure. When the pressure from the lungs is removed, they expand. With the expansion of the lungs vacuum is created inside the lungs in which the air rushes from the outside due to higher atmospheric pressure. This is called inspiration.

Q91. The boiling point of water is higher than other hydrides because water molecules can form:

• A. 4 hydrogen bonds✓
• B. 3 hydrogen bonds
• C. 2 hydrogen bonds
• D. 1 hydrogen bond

Explanation: Each water (H₂O) molecule can form four hydrogen bonds in total:2 hydrogen atoms → can each form 1 hydrogen bond (as donors)2 lone pairs on oxygen → can each form 1 hydrogen bond (as acceptors)Total = 4 hydrogen bonds per water molecule

Q92. In electrochemical series, elements are arranged in order of their standard electrode potentials, the correct decreasing reactivity order for metals is:

• A. Gold, silver, magnesium, aluminum
• B. Mercury, calcium, sodium, magnesium
• C. Sodium, aluminum, lead, copper✓
• D. Potassium, silver, magnesium, aluminum

Explanation: In the electrochemical series, metals with more negative standard electrode potentials are more reactive. Sodium is highly reactive, followed by aluminum, then lead, and finally the least reactive among them is copper. Thus, the correct decreasing reactivity order is Na > Al > Pb > Cu.

Q93. The oxidation state of Cl in HClO4 is:

• A. -1
• B. -5
• C. +7✓
• D. -7

Explanation: To determine the oxidation state of Cl in HClO4, we use the known oxidation states: +1 for hydrogen and -2 for oxygen. The equation is set up as:+1 (H) + Cl + 4(-2) (O) = 0.This simplifies to:+1 + Cl - 8 = 0.Solving for Cl gives Cl = +7. Therefore, the oxidation state of Cl is +7. The incorrect options result from miscalculations or misapplications of the oxidation state rules.

Q94. In which of the following nitrogen compounds, does N has the highest oxidation state?

• A. NH2OH
• B. N2H4
• C. HNO3✓
• D. NH3

Explanation: HNO3 has the highest oxidation state of nitrogen atom:+1+x+(-6)=0x=+5In NH3, N2H4, and NH2OH, the oxidation states, when calculated the same way, are 3-, 2+, and 1+ respectively.

Q95. Which one of the following vitamins Is required for normal growth, vision, and keeping the skin healthy?

• A. Vitamin D
• B. Vitamin E
• C. Vitamin A✓
• D. Vitamin K

Explanation: Vitamin A. Both the upper and lower layers of skin need vitamin A. It seems to prevent sun damage by interrupting the process that breaks down collagen. Since it's an antioxidant, it may give your skin some protection against sunburn (although not as much as wearing sunscreen).Vitamin A seems to help the growing tissues in a baby in the womb. It also helps the placenta form during pregnancy. Vitamin A is an important factor in growth throughout life. Vitamin A helps grow and maintain epithelial tissues.A group of antioxidants, vitamin A not only is beneficial to a healthy functioning ocular surface but also is required for the formation of the photoreceptor rhodopsin. This photopigment found in rod cells of the retina is especially helpful in allowing our eyes to see at night.

Q96. Which one of the following is the pure carbon compound and used as a reducing agent in industries?

• A. Coal tar
• B. Petroleum
• C. Coal gas
• D. Coke✓

Explanation: Coke is almost pure carbon obtained from destructive distillation of coal Because of its high carbon content, it is widely used as a reducing agent in metallurgical industries. Coal tar, petroleum, and coal gas are mixtures, not pure carbon.

Q97. 106 gram of Na2CO3 per dm3 of the solution of Na2CO3 in water, the concentration of the solution will be:

• A. 1N
• B. 0.1 M
• C. 1M✓
• D. 0.02M

Explanation: Na2CO3=23(2)+12+16(3)=46+12+48= 106Concentration=Given mass/molar massConcentration= 106/106 = 1M.

Q98. Which of the following properties depends upon the amount of matter present in the system?

• A. Density
• B. Gibbs free energy✓
• C. Pressure
• D. Temperature

Explanation: Gibbs free energy is an extensive property that depends upon the amount of substance present in the system. If the matter in a given system at a given condition is divided into two equal parts, the values of the extensive properties will become half of the original values. Other extensive properties include mass, volume, moles, enthalpy, entropy, and internal energy.

Q99. For the following exothermic reaction, a decrease in temperature will shift the equilibrium towards: 2NO(g) + O2 (g) -> 2NO2 (g)

• A. Left
• B. The Point of Equilibrium
• C. Both Directions
• D. Right✓

Explanation: For an exothermic reaction like 2NO (g) + O2 (g) ⇌ 2NO2 (g), a decrease in temperature will shift the equilibrium towards the right. This shift helps to increase the temp as heat is released in exothermic reactions, as the reaction is exothermic in the forward direction. Therefore this option is correct.

Q100. When electricity is passed through water in the presence of an acid, oxygen and _ are produced.

• A. Carbon
• B. CO
• C. CO2
• D. Hydrogen✓

Explanation: When electric current is passed through water, water dissociates into hydrogen and oxygen. Hydrogen is deposited over the negative pole and oxygen is deposited over the positive pole. Deposition of hydrogen and oxygen at different poles is visible in the form of bubbles.

Q101. Lithium and Beryllium are unique in such a way that they have higher charge densities which produce strong polarizing effects due to:

• A. Non-metal
• B. Solubility
• C. Small Size✓
• D. Large size

Explanation: Smaller size is the main cause of high charge density and increasing polarizing effect. The polarizing power of a cation is inversely proportional to its size. Smaller is the size of the cation and higher will be its charge density, which means greater concentration of charge on a smaller area. The more will be the charge density, higher will be its polarising power.

Q102. The number of bond(s) between carbon and nitrogen atoms in a Nitrile is:

• A. One sigma and one pi
• B. Two sigma and one pi
• C. Only sigma
• D. One sigma and two pi✓

Explanation: Both the carbon and the nitrogen are sp hydridized which leaves them both with two p orbitals which overlap to form the two π bond in the triple bond. The bond angle in nitrile is 180° which give a nitrile functional group a linear shape.

Q103. How many chain isomers are shown by C5H12?

• A. 5
• B. 4
• C. 3✓
• D. 2

Explanation: C5H12 can have 3 isomers.

Q104. Which of the following gases is used for welding purpose:

• A. Ethene
• B. Ethane
• C. Propane
• D. Ethyne✓

Explanation: Ethyne, or acetylene, is the correct choice for welding purposes. It is favored in the industry for its ability to produce a flame temperature over 3600K when burned with oxygen, allowing it to cut and weld metals efficiently. The other gases listed, such as ethene, ethane, and propane, do not reach the necessary temperatures or have other primary uses that do not include welding.

Q105. Which one of the following bonds has the highest bond energy?

• A. .C-C
• B. .C ≡ C
• C. N ≡ N✓
• D. H-F

Explanation: Triple bonds are stronger than single and double bonds, for understandable reasons. A nitrogen-nitrogen triple bond is stronger than a carbon-carbon triple bond because as we know that in the periodic table as we move from left to right the atomic sizes of elements decrease, this is due to the addition of electrons in the valence shell which increases nuclear charge. Carbon and nitrogen both elements are present in the same period but nitrogen (Z=7) is placed next to carbon (Z=6) thus it means the size of nitrogen is smaller than that of carbon and thus both the nitrogen atoms are much closer to each other unlike in case of carbon and hence more energy is required to break N-N triple bond compared to C-C triple bond.

Q106. The nature of positive rays depends on:

• A. The nature of the electrode:
• B. The nature of the discharge tube
• C. The nature of the residual gas.✓
• D. The shape of the electrode

Explanation: The nature of positive rays produced in a vacuum discharge tube depends upon the nature of the residual gas-filled. The positive rays consist of positive ions obtained by removing one or more electrons from gas molecules.

Q107. Tritium, an isotope of hydrogen contains:

• A. Equal number of electrons and neutrons
• B. Equal number of electrons, protons and neutrons
• C. Number of neutrons is double than the number of protons✓
• D. Number of neutrons is half than the number of protons

Explanation: Tritium is the isotope of the hydrogen having mass number 3 and proton number 1.Number of neutrons are mass number-number protons which turn out to be 2. So we can say that the number of neutrons is twice the number of protons.

Q108. When 3d orbital is complete, the next entering electron goes into:

• A. 4f
• B. 4s
• C. 4p✓
• D. 4d

Explanation: The correct order of electron orbital filling is determined by the Aufbau principle, which states that electrons fill orbitals starting from the lowest energy level to the highest. The sequence is: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, and so on. After the 3d orbitals are complete, the next electrons go into the 4p orbitals, making 4p the correct answer. Options 4f and 4d are filled much later in the sequence, and 4s is filled before 3d.

Q109. What is the order of the following reaction:2NO +O2 -> 2NO2

• A. 0
• B. 1
• C. 2
• D. 3✓

Explanation: The order of a chemical reaction is determined by the sum of the powers of the concentration terms in the rate law. For the reaction 2NO + O2 → 2NO2, the rate law is typically based on experimental data, but it can be inferred that the reaction is third-order: second-order with respect to NO and first-order with respect to O2. Therefore, the overall reaction order is 3. This is why Option D is correct, while Options A, B, and C do not accurately reflect the stoichiometry and concentration dependence of the given reaction.

Q110. Paramagnetic elements contain:

• A. All paired electrons
• B. All unpaired electrons
• C. Few unpaired electrons.✓
• D. Unequal electrons and protons

Explanation: Paramagnetic elements are those with one or more unpaired electrons. These unpaired electrons create a net magnetic moment, making the element attracted to an external magnetic field. Option C is correct because it acknowledges the presence of unpaired electrons, which is the primary cause of paramagnetism. Option A is incorrect because paired electrons result in diamagnetism, not paramagnetism. Option B is misleading as it implies that all electrons must be unpaired for paramagnetism, which is not true. Even one unpaired electron can result in paramagnetism. Option D is unrelated to paramagnetism; it describes ions, which have an imbalance of electrons and protons, resulting in a charge.

Q111. The rate of E1 reaction depends upon:

• A. Concentration of the nucleophile
• B. Concentration of the substrate as well as the alkyl halide
• C. Concentration of the substrate only✓
• D. None of these

Explanation: The E1 (elimination, unimolecular) reaction proceeds in two steps, with the first step—the formation of a carbocation— being the slow, rate-determining step. Since only the substrate (alkyl halide) is involved in this step, the rate of the reaction depends only on the concentration of the substrate.

Q112. Name the main product formed as a result of the following reactionH3C - (CH2)5 - CH3 ————> Product n-heptaneConditions: 480 - 550 C, 150 - 399 psi V2O5

• A. Benzene
• B. Toluene✓
• C. Xylene
• D. Cyclohexane

Explanation: The above reaction leads to cyclization of n-heptane followed by the aromatization of that cyclic ring, this forms toluene, option B is correct. Benzene is the wrong option because benzene has six carbon while n-heptane has 7 carbon atoms. Cyclohexane is also the wrong option for the same reason. Xylene has 8 carbon atoms while our reactant has 7 carbon atoms.

Q113. In a zero-order reaction, the rate is independent of:

• A. The temperature of the reaction
• B. The concentration of reactants✓
• C. The concentration of products
• D. The presence of a catalyst

Explanation: In a zero-order reaction, the rate of reaction is independent of the concentration of reactants. This means that even if the concentration of reactants changes, the rate remains constant. This is distinct from other reaction orders, where the rate depends on the concentration of one or more reactants. Temperature affects the rate of reaction as it influences kinetic energy and collision frequency. Catalysts accelerate the reaction rate by providing a lower-energy pathway, and product concentration can shift equilibrium but does not directly affect the rate of a zero-order reaction.

Q114. Which of the following molecules have zero dipole moments?

• A. NH3
• B. CHCl3
• C. H2O
• D. BF3✓

Explanation: The correct answer is BF3. BF3 is a trigonal planar molecule with symmetrical geometry, causing the dipole moments of the three B-F bonds to cancel each other out, resulting in a net dipole moment of zero. In contrast, NH3 has a trigonal pyramidal shape with a lone pair on nitrogen, resulting in a non-zero dipole moment. CHCl3 has a tetrahedral shape but lacks symmetrical distribution due to different atoms, which also results in a net dipole moment. H2O has a bent shape due to lone pairs, leading to a prominent dipole moment.

Q115. Which of the following ions has the largest heat of hydration?

• A. Na+
• B. Al3+✓
• C. F-
• D. Sr2+

Explanation: The heat of hydration is determined by the charge density of the ion, which is the ratio of its charge to its size. Al3+ has the highest charge (+3) and a small ionic radius, maximizing its charge density. This results in very strong interactions with water molecules and the largest heat of hydration among the options. In contrast, Na+ and F- have lower charges, and Sr2+ has a larger size, all of which lead to lower charge densities and smaller heats of hydration compared to Al3+.

Q116. Write the chemical name of the given structure.

• A. 4-ethyl-2,5-hexadiyne
• B. 3-ethyl-1,4-hexadiene
• C. 3-ethyl-1,4-hexadiyne✓
• D. 3-ethyl-2,5-hexadiyne

Explanation: The correct name for the compound is 3-ethyl-1,4-hexadiyne. Following IUPAC naming conventions, the longest carbon chain is hexane, with an ethyl group on the 3rd carbon. The '1,4-diyne' indicates triple bonds between the 1st and 2nd, and 4th and 5th carbons. Option A starts numbering from the wrong end, Option B incorrectly identifies the bonds as double bonds, and Option D uses incorrect numbering and punctuation.

Q117. Which of the following catalysts is used in the decomposition of laughing gas N2O at 1000 K?2N2O <-> 2N2 + O2

• A. Glycine
• B. V2O5
• C. Fe
• D. Traces of Cl2✓

Explanation: Cl2 is used as a catalyst in decomposition of N2O4.

Q118. The carbon number of gasoline is:

• A. .C5 - C6
• B. C6 -C7
• C. C5-C10✓
• D. C12-C15

Explanation: The hydrocarbons of gasoline contain typically C5-C10 carbon atoms.

Q119. For an equilibrium change involving gaseous phase, the forward reaction is first order while the reverse reaction is second order. The unit of Kp for the forward equilibrium is:

• A. atm✓
• B. atm2
• C. atm-1
• D. atm-2

Explanation: For a reaction where the forward reaction is first order and the reverse is second order, the equilibrium constant Kp for the forward reaction will have the unit of pressure raised to the power of the order of the forward reaction, which is atm. The units of Kp are derived from the partial pressures of the gases involved, and for a first-order reaction, the unit is simply atm. Other options such as atm2, atm-1, and atm-2 correspond to different reaction orders that do not match the given scenario.

Q120. The oxidation potential standard hydrogen electrode is arbitrarily taken as:

• A. -0.76 volts
• B. 0.00 volts✓
• C. +1.5 volts
• D. 1.0 volts

Explanation: The standard hydrogen electrode (SHE) is defined as having a potential of 0.00 volts under standard conditions (298 K, 1 atm, and solutions at 1 M concentration). This is because it serves as a universal reference point for measuring the electrode potentials of other half-cells. Other options such as -0.76 volts, +1.5 volts, and 1.0 volts are incorrect as they correspond to potentials of other electrodes or are arbitrary values not related to the SHE.

Q121. A gas that reacts with CaO and not with NaHCO3 is:

• A. None of these
• B. CI2✓
• C. O2
• D. N2
• E. Na

Explanation: Chlorine gas does react with calcium oxide (CaO) to form calcium chloride (CaCl2):Cl2 + CaO → CaCl2But it doesnot react with NaHCO3

Q122. The molecular structure of a hydrocarbon is shown below.

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

Explanation: B is a structural isomer of the structure shown above. Structure in A is the same as the structure shown. Structure C is not an isomer because it does not have the same number of carbon and hydrogen atoms as in the diagram shown. Structure D has a double bond that reduces two hydrogen atoms from it as compared to the structure shown that is why D can not also be an isomer of the diagram shown above.

Q123. Heat evolved or absorbed in a chemical reaction does not depend upon?

• A. Amount of reactants
• B. Pressure of reaction✓
• C. Physical state of reactants and products
• D. Temperature

Explanation: The correct answer is Pressure of reaction. Enthalpy is a thermodynamic state function that represents the heat content of a system. Under constant pressure conditions, the change in enthalpy (ΔH) reflects the heat evolved or absorbed during a chemical reaction and is independent of the pressure at which the reaction occurs, as long as the initial and final states are the same. This is because enthalpy is determined by the internal energy, pressure, and volume of the system, which are all state properties.Amount of reactants: This affects the total enthalpy change because more reactants generally lead to a larger heat change. Thus, it does affect the heat evolved or absorbed.Physical state of reactants and products: Different physical states have different enthalpy values (e.g., the enthalpy of vaporization or fusion), so this factor also affects the heat change.Temperature: Changes in temperature can affect the enthalpy of a system, as it influences the energy levels and distribution of molecules, thereby affecting the heat evolved or absorbed.

Q124. 1 mole of N2O4 (g) was placed in an empty 1 dm^3 container and allowed to reach equilibrium according to the following equation:N2O4(g) <-> 2NO2(g)At equilibrium, x mole Of N2O4 (g) had dissociated. What is the value of the equilibrium constant, Kc, at the temperature of the Experiment?

• A. 2x / (1 - x)
• B. 4x2 / (1 - x)2
• C. 2x / (1 - x)2
• D. 4x2 / (1 - x)✓

Explanation: This is the following solution:

Q125. Which of the hydrogen compounds has the highest percentage of ionic character?

• A. HCl
• B. HBr
• C. HI
• D. HF✓

Explanation: The ionic character of a bond is largely determined by the difference in electronegativity between the two bonded atoms. Fluorine has the highest electronegativity of all elements, resulting in the largest electronegativity difference between hydrogen and fluorine in HF. This large difference gives HF the highest percentage of ionic character among the given hydrogen compounds. In contrast, HCl, HBr, and HI have progressively lower electronegativity differences and hence lower ionic character, with HI having the lowest due to iodine's relatively low electronegativity.

Q126. Which of the following statements about H2S is false?

• A. It is a covalent compound
• B. It is a gas with bad smell
• C. It is a stronger reducing agent than H2O
• D. It is a weak base in water✓

Explanation: H2S acts as weak acid in water, not as a weak base. In H2S, the influence of the nucleus is less and hence, it can give away its electrons.

Q127. The amount of solute present in the given amount of solvent is called:

• A. Molarity
• B. Molality
• C. Concentration✓
• D. Solubility

Explanation: The concentration of the solution tells you how much solute has been dissolved in the solvent. For example, if you add one teaspoon to two cups of water, the concentration could be reported as 1 teaspoon salt per 2 cups of water.

Q128. In the reaction 2Fe+Cl2 -> 2FeCl3

• A. Fe is reduced
• B. Fe is oxidized✓
• C. Cl2 oxidized
• D. None of the above

Explanation: The Oxidation state of iron(Fe) is changed from "0" to "+3". Hence it is oxidised.

Q129. The formula of Plaster of Paris is:

• A. (CaSO4).1/2H2O✓
• B. (CaSO4).5H2O
• C. (CaSO4).7H2O
• D. (CaSO4).9H2O

Explanation: The chemical name of the Plaster of Paris is calcium sulphate hemihydrate because half a molecule of water is attached with calcium sulphate. The chemical formula of plaster of Paris is CaSO4.1/2H2O

Q130. If 4.6 gm of ethyl alcohol and 6.0 gm of acetic acid is kept at a constant temperature until equilibrium was established, 2.0 gm of unused acetic acid were present. What is the Kc?

• A. 2.0
• B. 3.0
• C. 4.0✓
• D. 5.0

Explanation: Initially the moles of ethyl alcohol are:4.6/46=0.1 mol and acetic acid are:6/60=0.1 mol.In the end, we have 2gm of acetic acid that means 2/60=0.0333 mol of acetic acid is left or conversely speaking 0.0667 mol of acetic acid reacted to produce the same amount of ethyl acetate and water.So now Kc can be calculated as we now at the final stage of reaction we have 0.0333 mol of acetic acid and thus 0.0333 mol ethyl alcohol present as reactants, as molar ratio is same in the equation. We also know that since 0.0667 mol reacted so ethyl acetate is present in the same amount as water.Kc=[0.0667]2/[0.0333]2=4.0

Q131. C12H22O11 + conc. H2SO4 → 12 C + ? + H2SO4

• A. 11 H2O✓
• B. 11 O2
• C. 11 CO2
• D. 11 H2

Explanation: Comparing reactant and product side we can see that there is a difference of 22 H and 11 O. That means the compound that we can make of it is 11 H2O. Hence the answer is A.

Q132. In SN1 reaction “1” stands for?

• A. Polar solvents
• B. Unimolecular✓
• C. Bimolecular
• D. Nucleophile

Explanation: The SN1 reaction is a substitution reaction in organic chemistry, the name of which refers to the Hughes-Ingold symbol of the mechanism. "SN" stands for "nucleophilic substitution", and the "1" says that the rate-determining step is unimolecular.

Q133. 22.4 dm3 of volume of each H2 and O2 are sparked to produce water vapours (considered as ideal gas) on completion of reaction. What is the decrease in the volume of the vessel?

• A. 44 dm3
• B. 22.4 dm3
• C. 33.6 dm3
• D. 11.2 dm3✓

Explanation: In the reaction, 2 moles of H2 react with 1 mole of O2 to form water vapor. Initially, there are 44.8 dm3 of gas (22.4 dm3 of each gas). According to the stoichiometry, 22.4 dm3 of H2 reacts with only 11.2 dm3 of O2, forming 22.4 dm3 of water vapor. The remaining 11.2 dm3 of O2 adds to the water vapor for a total final volume of 33.6 dm3. The initial volume was 44.8 dm3, so the decrease in the volume is 44.8 - 33.6 = 11.2 dm3. The other options misunderstand either the stoichiometry or the ideal gas volume concept.

Q134. In HF the covalent bond is due to:

• A. S-S overlapping
• B. S-Pz overlapping✓
• C. S-Px overlapping
• D. Pz - Pz overlapping

Explanation: In formation of HF, 1s orbital of H overlaps with 2Pz orbital to F to form bond. Therefore bonding is due to S-Pz overlapping.

Q135. Hydrogen resembles the elements of groups:

• A. I-A, V-A and VIII-A
• B. I-A, IV-A and VI-A
• C. I-A, II-A and VII-A
• D. I-A, IV-A and VII-A✓

Explanation: Hydrogen is unique in its periodic behavior but shows similarities to several groups. It resembles group I-A because it has one valence electron and can lose this electron to form a cation. It resembles group IV-A because it can share electrons, akin to the group IV-A elements with half-filled valence shells. Additionally, it resembles group VII-A in its ability to gain an electron and form an anion, similar to the halogens. The other options incorrectly associate hydrogen with groups where it does not demonstrate such chemical similarities.

Q136. A thermocouple is immersed in water at 373 K and the other in ice at 273K. The emf of the thermocouple Is 90 (μ)V for each 1 K difference in temperature between junctions, and the thermocouple resistance is 6 Ω. What current will flow in the galvanometer connected in series with an internal resistance of 30 ohms?

• A. 1.8 μA
• B. 250 μA✓
• C. 300 μA
• D. 1.5 mA
• E. 1.8 mA

Explanation: Given details: Galvanometer resistance = 30 ohm Thermocouple couple resistance = 6 ohm So, Total resistance = 30+6 = 36 ohm Temperature difference = 373K – 273K =100K Emf of thermocouple for 1K temperature difference = 90 microvolt = 90 × 10^-6 V So, for 100K, emf = 90 × 10^-6 x 100 = 90 × 10^-4 V Solution: Current flow in galvanometer = Voltage / Resistance I = 90 × 10^-4 / 36 =0.00025 A = 250 micro Ampere

Q137. A car covers the first half of a certain distance with a speed V1 and the second half, with a speed V2. Find the average speed during the whole journey?

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

Explanation: Average speed= total distance/total timeThe car’s journey can be divided into two equal parts of distance ‘d’. Since both distances are equal,Total distance= 2dTotal time= d/v1 (for first part) and d/v2 (for second part)Average speed= 2d / d(1/v1+1/v2)d cancels out leaving 2 / (v1+v2/v1v2)Which can be written as 2v1v2 / v1+v2That is consistent with option B.

Q138. A battery has an e.m.f of 6.0 volts and an internal resistance of 0.4 ohms. It is connected to a 2.6 ohms resistor through a SPST (single pole, single throw switch). When the switch is open, the potential difference between the terminal of the battery is:

• A. 0 V
• B. 0.8 V
• C. 2.6 V
• D. 5.2 V
• E. 6.0 V✓

Explanation: The emf of a battery is generated by the chemical action in the battery. When no current is being drawn from the battery, the difference in potential between the terminals is equal to the emf.

Q139. The following question belongs to the topic of momentum:

• A. Current
• B. Length
• C. Angular momentum✓
• D. Torque
• E. Displacement

Explanation: The correct answer is Angular momentum. In three-dimensional space, the angular momentum of a point particle is defined as the cross product of its position vector (r) with respect to a given origin and its linear momentum vector (p). This forms a pseudovector, which is essential in describing rotational motion in physics. The other options are incorrect because they do not correctly describe the properties or definitions related to momentum or angular momentum. 'Current' relates to electric charge flow, 'Length' and 'Displacement' relate to measures of distance, and 'Torque' is a measure of rotational force, not a type of momentum.

Q140. The instrument(s) which work on the principle of Wheatstone bridge is/are:

• A. Meter Bridge
• B. The Post Office Box
• C. Carey Foster's Bridge
• D. Calendar
• E. A, B and C✓

Explanation: All of the above mentioned instruments work upon the principle of Wheatstone bridge to measure the resistance except calendar.The Wheatstone bridge works on the principle of null deflection, i.e. the ratio of their resistances is equal, and no current flows through the circuit. Under normal conditions, the bridge is in an unbalanced condition where current flows through the galvanometer.All of the given examples work on this principle.

Q141. The scalar product of (2i - j + 3k).(3i + 2j - k)?

• A. 1✓
• B. 2
• C. 10
• D. 20
• E. 25

Explanation: The scalar product (also known as the dot product) of two vectors is calculated by multiplying their corresponding components and adding the results: (2i-j+3k) • (3i+2j-k) = 2×3 + (-1)×2 + 3×(-1) = 6 - 2 - 3 = 1. Options B, C, D, and E are incorrect as they result from miscalculations in either the component multiplication or the addition of these products.

Q142. Assume that you have two balls of Identical volume, one weighing 2 Newtons and the other 10 Newtons. Both are falling freely after being released from the same point simultaneously. Which of the following will then be true: I. The 10 N ball falling freely from rest will be accelerated at a greater rate than the 2 N ball II. At the end of the 4s of freefall, the 10 N ball will have 5 times the momentum of the 2 N ball III. At the end of the 4s of free fall, the 10 N ball will have the same kinetic energy as the 2 N ball IV. The 10 N ball possesses greater inertia than the 2 N ball

• A. I, Il and Ill only
• B. I and II only
• C. II and IV only✓
• D. IV only
• E. None of these

Explanation: Acceleration of free fall acts equally on all masses, this is why both objects despite having different masses have the same speed at any point in time. Statement II is correct because two objects have the same velocity but one having 5 times more mass than the other will have 5 times more momentum than the other object. Statement IV is also correct because inertia depends upon mass since a 10N ball has a higher mass it will have greater inertia. Statement III is wrong because objects have different masses so their kinetic energy can not be the same. Statement I is wrong because objects accelerate irrespective of their masses as mentioned before.

Q143. A point source of light is placed at the principal focus of a concave lens. Which of the following will be true of the refracted light?I- I will diverge.II- It will be paralel to be principle axis.III- It will seem to come from a point 1/2 of the radius of curvature from the lens.IV- It will converage.

• A. I, II and III Only
• B. I and III only
• C. II and IV only
• D. IV only
• E. None of the above✓

Explanation: Statement I is correct because a concave lens is diverging.Statement II is incorrect because the refracted rays will not be parallel to the principal axis.Statement III is incorrect because this is not true.Statement IV is incorrect because a concave lens is diverging while a convex lens is converging. Judging from our deductions about the statements, none of the options A, B, C, or D are correct. Hence option E is the right answer.

Q144. A body of mass 0.025 kg attached to a spring is displaced through 0.1 m to the right of the equilibrium position. If the spring constant is 0.4 =N/m and its velocity at the end of displacement is 0.4 m/sec, then its total energy will be:

• A. 4 x 10-3 J✓
• B. 0.0002 J
• C. 0.000001 J
• D. 0.2 J
• E. 0.04 J

Explanation: The total energy of the object is equal to the energy possessed by it due to motion(kinetic) and potential(potential in the spring). As shown below:

Q145. If A = 2i + 3j - k , B = 4i + 2j - 2k . Find a vector x which is parallel to A but has the magnitude of B?

• A. √(12/7) (2i + 3j - k)✓
• B. √(7/12) (4i + 2j - 2k)
• C. √(7/12) (2i + 3j + k)
• D. √(3/5) (i + 2j - 3k)
• E. √(5/12) (3i + 5j - 2k)

Explanation: The magnitude of B is equal to √(4)² + (2)² + (2)²=√24The magnitude of A is equal to √(2)² + (3)² + (1)² =√14The parallel vector is proportional to vector A.=>√24/√14 (2i + 3j - k)=>√(12/7) (2i + 3j - k)

Q146. The half-life of C14 is about:

• A. 1637 years
• B. 892 years
• C. 10 years
• D. 100 years
• E. 5730 years✓

Explanation: Carbon-14 has a half-life of 5,730 ± 40 years—i.e. half the amount of the radioisotope present at any given time will undergo spontaneous disintegration during the succeeding 5,730 years.

Q147. Two capacitors C1=3 uF and C2=6 uF are in series across a 90 volts D.C. supply. The total capacitance is given by:

• A. 9 uF
• B. 2 uF✓
• C. 10 uF
• D. 90 uF
• E. 5 uF

Explanation: 1/C1 + 1/C2 = 1/C⅓ + ⅙ = 1/C2 + 1 /6 = 1/C3/6 = 1/C½ =1 /CC = 2 uF

Q148. A 100 watt bulb is operated by 240 volts, the current through the bulb will be:

• A. 2.4 A
• B. 240 A
• C. 0.416 A✓
• D. 41.6 A
• E. 416 A

Explanation: Power = voltages * current100 = 240*ICurrent = I = 10/24= 5/12= 0.4166A

Q149. A car is travelling in a straight line along a highway at a constant speed of 80miles per hour for 10 seconds. Find its acceleration.

• A. 100 m/s2
• B. 200 m/s2
• C. 0 m/s2✓
• D. 150 m/s2
• E. 220 m/s2

Explanation: The correct answer is 0 m/s2. When a car is traveling at a constant speed, its velocity remains unchanged over time. Acceleration is calculated as the change in velocity divided by the time taken for that change. Since there is no change in velocity, the acceleration is zero. The other options suggest positive values for acceleration, which would imply a change in velocity, contradicting the condition of constant speed.

Q150. Two vectors S and R are such that S= 4, R= 6 and S.R= 13.5. Find the angle between S and R.

• A. 11.77
• B. 22.99
• C. 55.77✓
• D. 77.81
• E. 99.18

Explanation: S.R = lSl lRl cos (theta) 13.5=(4)(6) cos (theta) Cos -1 (13.5/24) =theta Theta= 55.77 So, option C is correct. As this question is theroretical options A, B, D and , E are incorrect.

Q151. An object is dropped from the top of the building. If it takes 10 seconds to hit the ground, what is the height of the building?

• A. 390 m
• B. 490 m✓
• C. 590 m
• D. 690 m
• E. 790 m

Explanation: The object is dropped, meaning its initial velocity vi is zero. Using the equation for uniformly accelerated motion h = vixt + ½gt², and substituting t = 10s and g = 9.8 m/s², we calculate the height: h = 0*10 + ½*(9.8)*(10)² = 490 m. Thus, option B is correct.Options A, C, D, and E result from miscalculations or incorrect application of the formula, leading to values that are either too low or too high.

Q152. The rate of change of angular velocity with respect to _ defines angular acceleration.

• A. Speed
• B. Frequency
• C. Distance
• D. Time✓
• E. Gravity

Explanation: Angular acceleration is defined as the rate of change of angular velocity with respect to time. This means it describes how quickly the speed of rotation is changing, and is typically measured in radians per second squared (rad/s^2). None of the other options—speed, frequency, distance, or gravity—relate directly to this rate of change. Speed and distance are linear measures, frequency is a measure of cycles per time but not change rate, and gravity is a force, not a measure of change in motion over time.

Q153. A body of mass 5 kg, initially at rest, is moved by a horizontal force of 2N on a smooth horizontal surface. Find the work done by the force in 10 sec:

• A. 40 J✓
• B. 30 J
• C. 50 J
• D. 20 J
• E. 10 J

Explanation: according to the formula of work (W=fd) we need to find the distance travelled, in order to do that we will find the acceleration firstacceleration = F/m=2/5 a = 2/5 m/s² Then we find the distance covereds=1/2at² (initial speed will be considered as 0) s=1/2*2/5*10² s = 2/10*100 s = 20m finally, we use the formula w=F.S w=2*20 w=40 J.

Q154. The radius of the moon is 27% off the earth’s radius and its mass is 1.2% of the earth's mass. Find the acceleration due to gravity on the surface of the moon:

• A. 0.431 m/s2
• B. 1.615 m/s2✓
• C. 2.431 m/s2
• D. 3.615 m/s2
• E. 4.431 m/s2

Explanation: Let M & M' be the mass of earth & moon. Also R & R' be their radius respectively. Given is - M' = 1.2% M = 0.012 M R' = 27% R = 0.27 R Gravitationalacceleration on earth's surface is - g = GM / R2 Gravitationalacceleration on supposed planet is - g' = GM' / R'2 g' = G(0.012M) /(0.27R)2 g' = (0.012/0.272)GM/R^2 g' = 0.1646 g g' = 0.1646 × 9.8 g' = 1.613 m/s2 Therefore, acceleration due to gravity on the moon's surface is 1.613 m/s2.

Q155. A sample of an ideal gas occupies a volume "V" at pressure "p" and absolute temperature "T". The mass of each molecule is 'm'. If "k" is the Boltzmann constant then the density of the gas is:

• A. mkT
• B. P/KT
• C. P/kTV
• D. mP/kT✓
• E. 2mPT/k

Explanation: PV= NkTV= NkT/PThe mass of one molecule of gas is ‘m’So total mass= N*mThe density of the gas is = total mass/ total volumeDensity= N*m/ (NkT/P)Which simplifies to mP/kT That is consistent with option D.

Q156. What will be the position of the object, when a convex lens of focal length 20 cm, is used to form an erect image which is twice as large as the object.

• A. 10 cm✓
• B. 20 cm
• C. 30 cm
• D. 40 cm

Explanation: This is the correct answer. To form an erect image twice as large as the object using a convex lens, the object must be placed between the focal point and the optical center of the lens. Focal length (f): 20 cm Magnification (m): 2 (since the image is twice as large as the object)Using the lens formula:1/v - 1/u = 1/fWhere: v is the image distance u is the object distanceSince the magnification is positive for an erect image:m = v/u = 2Therefore: v = 2uSubstituting this into the lens formula: 1/(2u) - 1/u = 1/20 cmSolving for u:u = 10 cmTherefore, the object must be placed 10 cm from the lens to form an erect image twice as large as the object.

Q157. A neutron travels a distance of 12 m in a time interval of 3.6 x 10-4 s. Assuming its speed was constant, its kinetic energy is: (take 1.7 x 10-27 kg as the mass of neutron)

• A. 3.1 eV
• B. 4.7 eV
• C. 5.78 eV✓
• D. 6.91 eV
• E. 7.81 eV

Explanation: speed of neutron = distance traveled by neutron/time taken by neutron to cover that distance. speed of neutron = 12/3.6 × 10^-4 m/s speed of neutron ( V)= 3.3 × 10⁴ m/s now, kinetic energy = 1/2mv² K.E = 1/2 × 1.7 × 10^-27 ×( 3.3 × 10⁴)²j = 1/2 × 1.7 × (3.3)² × 10^-19 j =9.2565 × 10^-19 j we know, 1ev = 1.6 × 10^-19 j so, K.E = 9.2565 × 10^-19/1.6 × 10^-19 ev = 9.2565/1.6 ev = 5.785 ev

Q158. If a voltage of 9V is applied between ends of a wire whose resistance is 0.2 ohm, what will be the resulting current?

• A. 30
• B. 35
• C. 40
• D. 45✓
• E. 93

Explanation: V=9 volts R=0.2 ohm I= ? V=IR => I = V/R I = 9 volts / 0.2 ohm I = 45 Ampere So , option D is correct.As this question is theoretical, options A, B, C and E are all incorrect.

Q159. If the potential difference of 1 volt is applied across the end of a conductor and the current flowing through the conductor is one ampere, then the resistance of the conductor is said to be?

• A. 1 Farad
• B. 10 Coulomb
• C. 1 Ohm✓
• D. 1 Coulomb
• E. 10 Ohm

Explanation: According to Ohm's Law, V = IR, where V is the potential difference, I is the current, and R is the resistance. Given a potential difference (V) of 1 volt and a current (I) of 1 ampere, the resistance (R) is calculated as R = V/I = 1 volt / 1 ampere = 1 ohm. Therefore, the correct answer is 1 Ohm.Options involving farads and coulombs are incorrect because they are units for capacitance and electric charge, respectively, not resistance. The option of 10 ohms is incorrect as it does not match the calculated resistance using the given values.

Q160. If an object is placed 30 cm from a convex loin whose local enuth is 15 cm, the size of the image compared to the size of the object will be approximately:

• A. Twice as large
• B. More than twice as large
• C. 1.5 times as large
• D. Smaller
• E. The same size✓

Explanation: For an object placed at twice the focal length of a convex lens, the image will be inverted, real, and the same size. So the correct answer here should be E. This can be confirmed using a ray diagram.

Q161. Fusion and fission reactions are associated with:

• A. Water or hydal energy
• B. Geothermal energy
• C. Fossil fuel energy
• D. Nuclear energy✓
• E. Tidal energy

Explanation: Both fission and fusion are nuclear reactions that produce energy, but the applications are not the same. Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy.

Q162. A particle is projected at an angle of 45 degrees with a velocity of 9.8 m/s. The horizontal range will be:(g=9.8 m/s2)

• A. 6.9 m
• B. 9.8 m✓
• C. 15.6 m
• D. 4.9 m
• E. 3.1 m

Explanation: Attached below is the solution to the question above:

Q163. A bulb having a resistance of 150 Ω is connected to a 225 volt source, the current in the bulb will be:

• A. 1.5 A✓
• B. 10 A
• C. 3.7350 A
• D. 250 A
• E. 100 A

Explanation: The correct answer is 1.5 A. According to Ohm's Law, which states V = I × R, you can determine the current I by rearranging the formula: I = V / R. Substituting the given values, I = 225 V / 150 Ω = 1.5 A. Other options are incorrect because they either miscalculate the division or assume incorrect values for voltage or resistance.

Q164. When a body moves in the direction of gravitational force i.e. towards the earth, the work is done by the force of gravity on the body and is _, whereas when the body moves against the direction of gravitational force, the corresponding work done is _.

• A. Negative, Positive
• B. Positive, Negative✓
• C. Positive, Positive
• D. Negative, Negative
• E. Insufficient Information

Explanation: When the work is done in the direction of the force then work done is said to be positive. However, if the work is in opposition to the direction of force then the work done is said to be negative.

Q165. In electronic circuits, a PN junction diode is used to convert alternating current into direct current. This process is called:

• A. Rectification✓
• B. Amplification
• C. Doping
• D. Integrated Circuit

Explanation: Rectification is the conversion of alternating current to direct current. Rectification is performed by a diode that allows current to flow in one direction but not in the opposite direction.

Q166. Which process is shown in the graph between pressure and volume given below?

• A. Adiabatic
• B. Isobaric
• C. Isochoric✓
• D. Isothermal

Explanation: The graph above shows that pressure is increasing while the volume remains constant.The processes in which the volume is constant are said to be isochoric in nature.

Q167. During radioactive decay of a nucleus zXA, β emission takes place along with the daughter nucleus. Because of this beta particle emission, the mass number (A) of the parent nucleus:

• A. Remains constant✓
• B. Decreases by 1
• C. Increases by 1
• D. Decreases by 2

Explanation: On emitting a β particle the number of nucleons in the nucleus (i.e. protons and neutrons) remains same, but the number of neutrons is decreased by one and the number of protons is increased by one.If a radioactive nucleus P with mass number A and atomic number Z emits a beta particle to form a daughter nucleus Q with mass number A and atomic number Z+1.(a) Atomic number Z is not conserved. It is increased by 1.(b) Mass number A is conserved.Result: So, from the above discussion it is clear thwt mass number (A) remains constant after the beta decay and not increased or decreased .

Q168. The shortest wavelength photon emitted in the Balmer series is:

• A. 1.0974 nm
• B. 4 nm
• C. 364.6 nm✓
• D. 3.64 m
• E. 480 nm

Explanation: Attached below is the solution to the question above:

Q169. A microscope has an objective of 10 mm focal length and an eyepiece of 25 mm focal length. What is the distance between the lenses, if the object is in sharp focus when it is 10.5 mm from the objective?

• A. 115 mm
• B. 235 mm✓
• C. 417 mm
• D. 716 mm
• E. 617 mm

Explanation: The correct answer is 235 mm. To find the distance between the lenses, use the formula: 1/f = 1/v - 1/u for the objective lens, where f is the focal length of the objective lens, u is the distance of the object from the lens, and v is the image distance. For the given microscope, f = 10 mm, and u = 10.5 mm. Solving for v, we get v = 210 mm. The total length of the microscope, which is the sum of v and the focal length of the eyepiece (25 mm), gives us 235 mm. The other options are incorrect due to errors in applying the lens formula or arithmetic mistakes in the calculations.

Q170. Equations of kinetics are valid only when the acceleration is:

• A. Increasing
• B. Decreasing
• C. Constant✓
• D. Vary with time

Explanation: The equations of kinetics can be utilized for any motion that can be described as being either a constant velocity motion (an acceleration of 0 m/s/s) or a constant acceleration motion. They can never be used over any time period during which the acceleration is changing.○Equations of kinetics are only valid in uniform motion or non- accelerating motion or constant acceleration (a=0).

Q171. If a constant current is flowing through a coil, then the flux through that coil will become constant. In such types of arrangements, the electromotive force (emf) induced in the coil will be:

• A. Self-Inductance
• B. Zero✓
• C. Mutual-Inductance
• D. Back EMF

Explanation: The emf induced in a circuit is directly proportional to the time rate of change of the magnetic flux through the circuit. And if there is no change in flux so the induced emf is zero.

Q172. Statements:I. The farmers have decided against selling their Kharif crops to the government agencies.II. The government has reduced the procurement price of Kharif crops starting from last month to the next six months.

• 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 effects of independent causes

Explanation: The reduction in the procurement price of crops must have instigated the farmers not to sell their produce to government agencies.

Q173. Complete the series A25, B625, C15625, _?

• A. D390625✓
• B. D364748
• C. D390524
• D. D390525

Explanation: Each number is multiplied by 25. 15625 x 25 is 390,625 hence, the answer is D390,625.

Q174. If '-' means'+', '+' means '-', '*' means '÷' and '÷' means '*' then which of the following will be the correct equation?

• A. 30 + 5 +14 -10 * 15 = 122
• B. 10 + 5 - 14 + 10 * 15 = 158
• C. 30 - 5 + 14 +10 * 15 = 162
• D. 30 * 5 - 4 + 10 - 30 = 30✓

Explanation: Option A: 30 + 5 +14 -10 * 15 = 122= 30 - 5 - 14 + 10 ÷ 15 (substituting the new symbols)= 30 - 5 - 14 + 0 (10 ÷ 15 = 0)= 11Option B: 10 + 5 - 14 + 10 * 15 = 158= 10 - 5 + 14 ÷ 10 - 15 (substituting the new symbols)= 10 - 5 + 1 - 15 (14 ÷ 10 = 1)= -9Option C: 30 - 5 + 14 +10 * 15 = 162= 30 + 5 - 14 - 10 ÷ 15 (substituting the new symbols)= 30 + 5 - 14 - 0 (10 ÷ 15 = 0)= 21 Option D: 30 * 5 - 4 + 10 - 30 = 30= 30 ÷ 5 + 4 - 10 + 30 (substituting the new symbols)= 6 + 4 - 10 + 30 (30 ÷ 5 = 6)= 30

Q175. Statement:There has been an unprecedented increase in the number of successful candidates in this year's School Leaving Certificate Examination.COURSE OF ACTION:I. The government should make arrangements to increase number of seats of intermediate courses in existing college.II. The government should take active steps to open new colleges to accommodate all these successful candidates.

• A. Both of them follow✓
• B. None of them follow
• C. Only I follows
• D. Only II follows

Explanation: Since the number of graduating/leaving candidates are greater, more applicants will be eligible for seats in colleges. The government should therefore accommodate these applicants. Thus, both statements follow.

Q176. StatementsI. She topped in her collegeII. She is hard-working

• A. Both statements are of some common cause
• B. Statement 1 is the cause and 2 is its effect
• C. Statement 2 is the cause then 1 is its effect.✓
• D. Both of the statements are effect of independent causes

Explanation: In order for her to top in her college, she must work hard. Hence, statement 2 is the cause and statement 1 is the effect.

Q177. If '-' means'+', '+' means '-', '*' means '÷' and '÷' means '*' then which of the following will be the correct equation?

• A. 30 + 5 +14 -10 * 15 = 122
• B. 10 + 5 - 14 + 10 * 15 = 158
• C. 30 - 5 + 14 +10 * 15 = 162
• D. 30 * 5 - 4 + 10 - 30 = 30✓

Explanation: Option A: 30 + 5 +14 -10 * 15 = 122= 30 - 5 - 14 + 10 ÷ 15 (substituting the new symbols)= 30 - 5 - 14 + 0 (10 ÷ 15 = 0)= 11Option B: 10 + 5 - 14 + 10 * 15 = 158= 10 - 5 + 14 ÷ 10 - 15 (substituting the new symbols)= 10 - 5 + 1 - 15 (14 ÷ 10 = 1)= -9Option C: 30 - 5 + 14 +10 * 15 = 162= 30 + 5 - 14 - 10 ÷ 15 (substituting the new symbols)= 30 + 5 - 14 - 0 (10 ÷ 15 = 0)= 21 Option D: 30 * 5 - 4 + 10 - 30 = 30= 30 ÷ 5 + 4 - 10 + 30 (substituting the new symbols)= 6 + 4 - 10 + 30 (30 ÷ 5 = 6)= 30

Q178. Each problem consists of three statements. Based on the first two statements, the third statement may be true, false, or uncertain.During the past year, Josh saw more movies than Stephen.Stephen saw fewer movies than Darren.Darren saw more movies than Josh.If the first two statements are true, the third statement is:

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

Explanation: The correct answer is 'Uncertain'. The first two statements tell us that Josh saw more movies than Stephen and Stephen saw fewer movies than Darren. Therefore, both Josh and Darren saw more movies than Stephen. However, the information provided does not allow us to definitively say whether Darren saw more or fewer movies than Josh. Options A and B are incorrect because the third statement's truth cannot be determined with certainty. Option D is incorrect because Option C is the correct choice.

Q179. Passage: There is a family of six persons G, J, B, E, T and Z. Their professions are teacher, writer, actor, singer, dancer and lawyer but not respectively in the same order. G is a teacher. Z is a dancer. B is neither writer nor actor. E is neither singer nor lawyer. T is an actor. J is a lawyer. Who among them has a profession of lawyer?

• A. J✓
• B. B
• C. E
• D. T

Explanation: The passage explicitly states, "J is a lawyer." Therefore, J is the person with the profession of a lawyer.

Q180. Statements: No building is a tree. All trees are living beings. Conclusions: I. No building is a living being. II. Some living beings are not buildings

• A. Only I
• B. Only II✓
• C. Both
• D. None

Explanation: Conclusion I: 'No building is a living being.' This conclusion cannot be derived from the given statements. The statements do not provide a direct relationship between buildings and living beings.Conclusion II: 'Some living beings are not buildings.' This conclusion is valid. Since all trees are living beings and no building is a tree, it follows logically that some living beings (specifically, trees) are not buildings.Thus, only Conclusion II is correct, making Option B the right choice.