Balochistan Mdcat Mock Paper 4 — Solved Past Paper with Answers

Q1. We prefer fruits _ sweets.

• A. Then
• B. On
• C. Over✓
• D. From

Explanation: The correct preposition to use in this case will be “over”. You prefer one thing “over” others.

Q2. Choose the correct spelling:

• A. Exantuated
• B. Axantuated
• C. Accenchuated
• D. Accentuated✓

Explanation: To "accentuate" means to “make more noticeable and prominent” and its correct spelling is given in Option D.

Q3. Choose the correct spelling:

• A. Defnite
• B. Defanit
• C. Dafanite
• D. Definite✓

Explanation: "Definite" is the correct spelling which means “to be on point”.

Q4. The headmaster _ to speak to you.

• A. Wants✓
• B. Is wanting
• C. Was wanting
• D. Want

Explanation: “The headmaster wants to speak to you” in Option A sounds most appropriate because "headmaster" is a singular noun so we should complement it with a singular verb - eliminating Option D. The tense is simple present indicated by the verb "speak", hence the present continuous form "is wanting" in Option B is also incorrect. while the past tense form in Option C is also incorrect.

Q5. Choose the correct option: Knowledge and wisdom _ no time for connection.

• A. Has
• B. Have✓
• C. Had
• D. Are

Explanation: The context of the sentence firstly requires a verb that satisfies the need to indicate the possession of "no time for connection" by "Knowledge and wisdom." Therefore the verb forms "is/am/are" which indicate "being" are not suitable here - eliminating Option D. Moreover, since the need for "no time" is being stated as a universal statement (everlasting) i.e. started in the past and continues to be true in the present, the tense should be present perfect. Hence, the verb form should include the helping verb "Have" as indicated by Option B.

Q6. Find the error in the following sentence:

• A. They have been✓
• B. Very close friends
• C. Until they quarelled
• D. Over a petty issue.

Explanation: 'They used to be close friends but not anymore' indicates that the sentence is in the past tense hence 'have been' will not be used. 'Had been' would be the correct term here. "Very close friends" is a correct description of the relationship between the two people. "Until they quarreled/quarrelled" is a correct way to indicate that their friendship ended due to an argument. "Over a petty issue" correctly identifies the cause of the quarrel.

Q7. I _ English since my childhood.

• A. Study
• B. Am studying
• C. Have been studying✓
• D. Studied

Explanation: Study: This option is in the present tense, which does not match with the time frame "since my childhood." To match the time frame, we need a present perfect or past perfect tense. 'Have been' suggests an action that started in the past, but continues in the present. Am studying: This option is also in the present tense and doesn't match the time frame mentioned. It also implies that the action is still ongoing, which may not be the case.Studied: This option is in the past tense, which does not indicate that the action started in the past and continues up to the present moment, as the sentence implies.

Q8. Some of the books on the table _ to me.

• A. Belong✓
• B. Belonging
• C. Belongs
• D. Was belong

Explanation: With pronouns like you, me, and we, 'belong' is used. "Belonging" is a gerund, which is a verb form that functions as a noun. It does not work in this context because the sentence requires a verb. "Belongs" is the singular form of the verb "to belong." Since the subject is plural ("books"), this form of the verb is not appropriate. "Was belong" is not a grammatically correct construction. The correct past tense form of "to belong" is "belonged," but the sentence is in the present tense, so this option is also not appropriate.

Q9. Have you _ the examination?

• A. Take
• B. Took
• C. Taken✓
• D. Taking

Explanation: Take - This is the present tense form of the verb, which is not appropriate for the context of the sentence. Took - This is the past tense form of the verb, which is not suitable for the present perfect tense used in the sentence. A helping verb precedes 'it' and for simple past tense, the word that should be used is 'taken': 'he has taken some other courses too.' Taking - This is the present participle form of the verb, which also does not fit the structure of the present perfect tense used in the sentence.

Q10. Choose the correct sentence:

• 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: Option A: This sentence is missing a comma before "and." It should be "an orange, and a pear." The absence of the comma makes the sentence grammatically incorrect.Option B: This sentence is also missing a comma before "and." Similar to option A, it should be "an orange, and a pear." The lack of a comma makes this sentence grammatically incorrect as well.Option C: This sentence is correctly punctuated with commas. It uses the comma before "and" when listing three items. Each item in the list is separated by a comma, and the final comma (known as the Oxford comma) is used before "and." This option is grammatically correct.Option D: Similar to options A and B, this sentence is missing a comma before "and." It should be "an orange, and a pear." The absence of a comma makes this sentence grammatically incorrect.

Q11. Measles _ a contagious childhood disease.

• A. Is✓
• B. Are
• C. Were
• D. Be

Explanation: Measles is a single disease that is why 'is' will be used.

Q12. She ran with quick steps to the house when it _ (start) raining.

• A. Start
• B. Starting
• C. Started✓
• D. Was started

Explanation: The word 'ran' indicates past tense therefore we will also use the past form of start.

Q13. Fetch _ chair and sit down.

• A. A✓
• B. An
• C. The
• D. No article is required

Explanation: A/an and the are articles. They are types of determiners and they go before a noun. Use “a” before words that start with a consonant sound and “an” before words that start with a vowel sound.

Q14. We went to the President as a last _.

• A. Recourse
• B. Resort✓
• C. Resource
• D. Resound

Explanation: "recourse" is a similar word that means seeking help or protection from someone or something when in difficulty or trouble, but it doesn't fit well in the given sentence. A last resort is a final course of action, used only when all else has failed. "resource" refers to a source of aid or support that can be drawn upon when needed. While it may be used in the same context as "last resort", it does not fit the given sentence. "resound" means to echo or reverberate with sound and has no connection to the given sentence.

Q15. How can the underlined word be changed? Mrs Rose planning to do a course in Biology next week.

• A. Are planning
• B. Plans✓
• C. With a plan
• D. Planning

Explanation: "Are planning" - This is the present continuous tense, which is grammatically correct and conveys a similar meaning as the original sentence. However, it changes the subject to plural, indicating that there are more people involved in the planning.As a verb, the word 'plans' can be used with a direct object or followed by on, for, and to."Plans" - This is the simple present tense, which indicates a habitual or regular action. While it is possible that Mrs Rose regularly plans to take courses in Biology, this tense does not convey the ongoing nature of the action."Planning" - This is the present participle.

Q16. Father must _ left his briefcase at the office.

• A. Of
• B. Had
• C. Have✓
• D. Opt

Explanation: We use "must-have" in the present perfect - the action we are describing happened, or did not happen, in the past and is still true in the present.

Q17. The excretion of hypertonic urine in humans is associated best with the:

• A. Glomerular capsule
• B. Proximal convoluted tubule
• C. Loop of Henle✓
• D. Distal convoluted tubule

Explanation: Hypertonic Urine means there is a higher solute concentration than the body fluid (the solution has more osmotic pressure; water moves in by osmosis). This means maximum water has been reabsorbed. Despite Option B, Option C, and Option D, playing a role in water reabsorption, the main site where water reabsorption occurs is the Loop of Henle. Glomerular Capsule (or the Bowman capsule, is a cup-like sac at the beginning of the nephron that is involved in the filtration of the blood coming into the kidney. The proximal Convoluted Tubule is present after the Bowman's capsule while the Distal convoluted tubule is present after the loop of Henle. The proximal Convoluted Tubule is the site where Sodium ions are reabsorbed while the Distal convoluted tubule is where the body carries our processes to maintain the body acid-base concentration. On the other hand, the Loop of Henle is associated with both the solute and water reabsorption using the counter-current multiplier, which involves the usage of energy to generate an osmotic gradient that enables the reabsorption of water from the filtrate and into the blood, producing concentrated urine.

Q18. In humans, the temperature regulation control center is located in:

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

Explanation: The body's temperature control center is the hypothalamus which itself is part of the brain. The hypothalamus via a network of thermoreceptors can sense when you are unusually hot. If so then the hypothalamus proceeds to send signals to your sweat glands to make you sweat and cool you off. When the hypothalamus senses that you're too cold, it sends signals to your muscles that make you shiver and create warmth. This is called maintaining homeostasis. The kidneys help to maintain homeostasis by regulating the concentration and volume of body fluids. Lungs are essential for the constant gaseous exchange of O2 and CO2. The liver plays an important role in the metabolism of nutrients in your body, detoxifying drugs, storing glycogen, synthesizing plasma proteins, etc. Hence, Option B is correct.

Q19. Coelom that develops from the archenteron as outpouching is?

• A. Pseudocoelom
• B. Schizocoelom
• C. Enterocoelom✓
• D. Both a and b

Explanation: 'Enterocoelom' is a coelom formed from the wall of the embryonic gut or enteron as hollow outgrowths. 'A' is not the answer because 'pseudocoelom' is the space between the body wall and the digestive tract and is not lined by the coelomic epithelium. 'B' is not the answer because the splitting of the mesoderm causes the formation of 'schizocoelom'.

Q20. Enzymes work by which of the following?

• A. Increasing the activation energy.
• B. Reducing the activation energy.✓
• C. Making exergonic reactions endergonic.
• D. Making endergonic reactions exergonic.

Explanation: Enzymes work by reducing the activation energy required for a chemical reaction to occur. The activation energy is the minimum energy input needed for reactant molecules to transform into products during a chemical reaction. It represents the energy barrier that must be overcome for the reaction to proceed. Enzymes facilitate reactions by providing an alternative pathway with a lower activation energy. The active site of an enzyme interacts with the substrate (reactant), bringing the reactants into close proximity and allowing the reaction to occur more easily. This reduction in activation energy accelerates the rate of the reaction and makes it more favorable under physiological conditions.

Q21. Among the followings which is the longest supportive cell?

• A. Trachea
• B. Collenchyma cells
• C. Sclereids
• D. Tracheids✓

Explanation: The trachea is an organ, not a cell so it cannot be Option A. Collenchyma cells can reach up to 2.5mm. Sclereids are typically 1mm. Tracheids are 7mm typically which is the longest hence the correct answer is Option D.

Q22. Which of the following is soluble in hot water?

• A. Starch
• B. Glycogen
• C. Amylose✓
• D. Amylopectin

Explanation: Out of all the options only amylose is soluble in hot water. Amylose is a linear polymer of glucose molecules that are linked together by α-1,4-glycosidic bonds. It is a long, unbranched chain that can form hydrogen bonds with water molecules. This allows amylose to dissolve in hot water. Amylopectin and glycogen are highly branched polymer of glucose molecules that are linked together by α-1,4- and α-1,6-glycosidic bonds. They are very large molecules and are insoluble in hot and cold water. Starch is a mixture of amylose and amylopectin in the ratio of 20% to 80%. As, amylopectin is present in a higher percentage in starch, starch is not completely soluble in hot water.

Q23. What is the strengthening material of the prokaryotic cell wall?

• A. Cellulose
• B. Chitin
• C. Silica waxes and lignin
• D. Peptidoglycan or murein✓

Explanation: Prokaryotic cell wall; It lacks cellulose. Its strengthening material is peptidoglycan or murein.

Q24. Which one is not the characteristic of Kingdom Animalia?

• A. All animals are ingestive heterotrophs
• B. All animals are eukaryotes
• C. It is the largest kingdom.
• D. All animals develop from the dissimilar gametes i.e. large sperm and the small egg✓

Explanation: The sperm is smaller in size than the ovum. A, B and C are true characteristics of animals.

Q25. As an excretory organ, liver:

• A. Detoxifies many chemical poisons
• B. Produces ammonia for excretion by the kidneys
• C. Produces urea and uric acids from the nitrogen of amino acids
• D. All of the above✓

Explanation: The liver has numerous functions in the human body, let's discuss each option one by one. A: The liver is an organ that comes into play after consumption of alcohol, as you can remember excess alcohol consumption can result in liver cirrhosis, where scarring occurs on the liver after continuous exposure to high amounts of alcohol. B&C: The urea cycle (also known as the ornithine cycle) occurs in the mitochondria of liver cells and results in the conversion of poisonous ammonia (NH3) to urea ((NH2)2CO) which is then excreted in the urine. All the above-mentioned metabolites are removed from the human body either directly (as in urea) or indirectly by further conversion into another substance. Hence, Option D is correct.

Q26. The active uptake of sodium in the ascending limb or thick loop of Henle is promoted by the action of:

• A. Aldosterone✓
• B. Thyroxine
• C. ADH
• D. Cortisone

Explanation: As a general principle, Sodium-Ion Concentration in the body is maintained by the hormone Aldosterone. The descending loop of Henle's loop is permeable to water. Water can be reabsorbed from the fluid inside the loop of Henle to the surrounding. The ascending loop of Henle's loop is impermeable to water. Sodium chloride is actively transported from the thick portion of the ascending limb without accompanying water. Hence, Option A is correct.Thyroxine is the main hormone secreted into the bloodstream by the thyroid gland. It plays vital roles in digestion, heart and muscle function, brain development, and the maintenance of bones. Thyroxine is produced by the thyroid gland, which stimulates the basal metabolic rate. It controls the speed at which oxygen and food products react to release energy for the body to use. Thyroxine plays an important role in growth and development. Thyroxine levels are controlled by negative feedback. The anti-diuretic hormone helps to control blood pressure by acting on the kidneys and the blood vessels. Its most important role is to conserve the fluid volume of your body by reducing the amount of water passed out in the urine.Cortisone is a steroid drug. It helps decrease swelling and inflammation in your body.

Q27. Which one of the following muscles are considered as “Voluntary muscles”?

• A. Smooth muscles
• B. Cardiac muscles
• C. Skeletal muscles✓
• D. Glandular muscles

Explanation: Functionally, our body has three categories of muscles i.e. Smooth, Cardiac, and Skeletal which are then further classified as voluntary and involuntary muscles. Voluntary muscles are muscles under conscious control i.e. they be controlled at will or we can choose when to use them. A good example of voluntary muscles is skeletal muscles which are responsible for the movement of body parts and locomotion. Hence, Option C is correct. On the other hand, involuntary muscles are those which are not under our conscious control. Examples of involuntary muscles include Smooth and Cardiac Muscles. Cardiac muscles contract on their own due to the self-excitable SA Node. Similarly, smooth muscles like glandular muscles contract automatically and release hormones when required.

Q28. The term ‘cell’ was given by

• A. Leeuwenhoek
• B. Robert Hooke✓
• C. Flemming
• D. Robert Brown

Explanation: The origins of the word 'cell' in the 1660s, Robert Hooke looked through a primitive microscope at a thinly cut piece of cork. He saw a series of walled boxes that reminded him of the tiny rooms, or cellula, occupied by monks.

Q29. The upward movement of sap by the xylem is:

• A. Ascent of sap✓
• B. Plasmolysis
• C. Deplasmolysis
• D. Guttation

Explanation: "The explanation for this question will be added soon!".

Q30. What is critical in photoperiodism?

• A. Length of light period
• B. Length of dark period✓
• C. Both Options A and B are correct
• D. None of these options is correct

Explanation: Both the length of the light period and the length of the dark period play important roles in photoperiodism. But, only length of dark period is critical in photoperiodism, because if plants are grown according to their short or long priods but only if their length of dark period is interrupted by a small period of light then their flowering is prevented.

Q31. A type of bacterial cell that is completely surrounded by flagella is called:

• A. Diplococcus
• B. Tetrad
• C. Peritrichous✓
• D. Monotrichous

Explanation: Diplococcus and Tetrad are some of the shapes of bacteria and are not related to flagella. Monotrichous means 1 flagella. Hence the correct answer is Option C peritrichous.

Q32. What is an example of sperms of liverworts, mosses, ferns which move towards archegonia, in response to nucleic acid released by the ovum?

• A. Chemotropic movement
• B. Chemonastic movement
• C. Haptonastic movement
• D. Chemotactic movement✓

Explanation: As nucleic acid is type of chemical signal for sperms so, that is why this chemical is sensed by sperm to reach ovum, Chemotactic is the movement of an organism or entity in response to a chemical stimulus and that is autonomic movement .

Q33. Which one of the following are “myogenic” type of muscles?

• A. Glandular muscles
• B. Cardiac muscles✓
• C. Skeletal muscles
• D. Smooth muscles

Explanation: The three muscle types (Cardiac, Smooth, Skeletal) can be further classified into two categories i.e. myogenic and neurogenic. Myogenic means originating in or produced by muscle cells themselves. Neurogenic means originating in or produced by nerve cells or neurons. The contractions of cardiac muscle fibers are described as myogenic, since they are produced spontaneously, without requiring stimulation from nerve cells. This is solely due to the presence of the SA and AV nodes on the heart, capable of producing electrical impulses to stimulate contraction. Single-unit visceral smooth muscle is myogenic; it can contract regularly without input from a motor neuron (as opposed to multiunit smooth muscle, which is neurogenic - that is, its contraction must be initiated by an autonomic nervous system neuron). Skeletal muscle on the contrary is neurogenic since it can contract when stimulated by a motor neuron. Hence, the only correct answer is Option B.

Q34. What do we call the cell surface membrane of a muscle fibre?

• A. Sarcolemma✓
• B. Plasma membrane
• C. Sarcoplasm
• D. Myofibrils

Explanation: 'Sarco-' literally means “muscle”. This prefix is used in terms of normal cell biology to indicate that the term is related to the muscles. On the other hand, '-lemma' means a “confining membrane”; for example, a normal cell’s membrane is simply referred to as the plasma membrane however, a muscle cell’s membrane is referred to as sarcolemma hence we reject option B. The cytoplasm of a striated muscle cell is referred to as 'Sarcoplasm' hence we reject option C as well. Myofibrils are made up of sarcomeres, the functional units of a muscle. The function of the myofibril is to perform muscle contraction via the sliding filament model.

Q35. Which of the following neurotransmitters function, both as neurotransmitter and hormones, decreasing our perception of pain?

• A. Epinephrine
• B. Serotonin
• C. Dopamine
• D. Endorphins✓

Explanation: Neurotransmitters are chemical messengers that transmit a message from a nerve cell across the synapse to a target cell. Hormones are chemical messengers that are secreted directly into the blood, which carries them to organs and tissues of the body to exert their functions. All the options are both, a hormone as well neurotransmitters. Epinephrine, commonly referred to as Adrenaline, relaxes the airway muscles, making it easier for the person to breathe. At the same time, it constricts blood vessels, helping to improve blood pressure. It also increases the heart rate. However, it does not decrease the response to pain. Hence Option A is rejected. Serotonin, on the other hand, is used by the body to send messages between nerve cells. It appears to play a role in mood, emotions, appetite, and digestion. As the precursor for melatonin, it helps regulate sleep-wake cycles and the body clock. Since it is not used to decrease pain response, Option B is rejected. Dopamine is a neurotransmitter that plays a role in how we feel pleasure. It's a big part of our unique human ability to think and plan. However, it plays no role in the pain response. Hence Option C is rejected. Endorphins are substances produced by the nervous system to cope with pain or stress. They are often called “feel-good” chemicals because they can act as pain relievers and happiness boosters. Hence, Option D is correct.

Q36. Which of the following wavelength is absorbed maximum for photosynthesis?

• A. 660 nm
• B. 680 nm
• C. 440 nm✓
• D. 700 nm

Explanation: Since chlorophyll absorbs maximum energy from the blue and red wavelength, blue light is absorbed maximum for photosynthesis than any other light and this color also comes first in the spectrum. A, B, and D are not the answers because of the above reason.

Q37. What are the subunits of capsids?

• A. Capsomere✓
• B. Flagella
• C. Hyphae
• D. Septa

Explanation: Capsomeres are tiny subunits that make up the protein coat, referred to as the capsid. Capsomeres are known as capsid subunits, which are the outer protective covering of proteins that protect the virus's genetic material. TMV is also known as the tobacco mosaic virus. It is a type of single-stranded RNA virus.

Q38. Inactive enzyme precursors such as pepsinogen for pepsin are called as:

• A. Holoenzymes
• B. Actinases
• C. Zymogens✓
• D. Mucopolysaccharides

Explanation: A 'zymogen' or proenzyme is an inactive enzyme precursor. A zymogen requires a biochemical change such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active site for it to become an active enzyme. 'Holoenzymes' are the active forms of enzymes. Glycosaminoglycans or mucopolysaccharides are long unbranched polysaccharides consisting of a repeating disaccharide unit. Actinases are not inactive enzymes. Thus, option 'C' is correct.

Q39. When two or more clearly different phenotypes exists in same population of species, the phenomenon is called?

• A. Replication
• B. Polymorphism✓
• C. Gene linkage
• D. Gene expression

Explanation: Polymorphism refers to the coexistence of two or more distinct forms or variants of a gene or trait within a population. These different forms, known as alleles, are found at a particular gene locus, and each allele may encode a slightly different version of the trait or protein. Polymorphism is a crucial concept in genetics and evolution, as it contributes to the diversity and adaptability of populations and plays a role in shaping the characteristics of individuals within a species.

Q40. Which of these structures transports sperm from the testis to the penis?

• A. Sperm duct✓
• B. Scrotum
• C. Urethra
• D. Gamete

Explanation: The structure that transports sperm from the testes to the penis is the vas deferens. The vas deferens is a duct that is part of the male reproductive system. It extends from the epididymis, where sperm mature and are stored, through the inguinal canal, and it eventually joins with the duct from the seminal vesicle to form the ejaculatory duct. The ejaculatory duct then passes through the prostate gland and empties into the urethra, which extends through the penis. During ejaculation, sperm travel through the vas deferens to reach the urethra and are then expelled from the body through the penis.

Q41. The stretch reflex, the Golgi tendon reflex, the crossed extensor reflex, and the withdrawal reflex are included in:

• A. Stretch reflex
• B. Spinal reflex✓
• C. Golgi tendon reflex
• D. Crossed Extensor Reflex

Explanation: The spinal reflex includes the stretch reflex, the golgi tendon reflex, the crossed extensor reflex and the withdrawal reflex.

Q42. Proteins are the polymers of?

• A. Amino acids✓
• B. Fatty acids
• C. Nucleotides
• D. None of these

Explanation: Proteins are madeup of amino acids.

Q43. Coccobacillus has a shape similar to which of the following?

• A. Rod
• B. Egg✓
• C. Ball
• D. None of these

Explanation: A coccobacillus is a bacterial shape that is similar to an oval or spherical shape. It is a type of bacterium that appears intermediate between cocci (spherical bacteria) and bacilli (rod-shaped bacteria). Coccobacilli are characterized by their short and rounded rod shape, often appearing as ovals or elongated cocci. They can vary in size and dimensions depending on the specific bacterial species.

Q44. Nicotinamide adenine dinucleotide is an example of:

• A. Coenzymes✓
• B. Holoenzymes
• C. None of these
• D. Both of these

Explanation: A coenzyme is defined as an organic molecule that binds to the active sites of certain enzymes to assist in the catalysis of a reaction. NAD is the most important coenzyme as well as cofactor in a eukaryotic cell. Not surprisingly, NAD and the closely related NADP are the two most abundant cofactors in eukaryotic cell.

Q45. The loss of liquid via the hydathodes is called:

• A. Imbibition
• B. Guttation✓
• C. Plasmolysis
• D. None of these

Explanation: "The explanation for this question will be added soon!".

Q46. Which body function is controlled through a positive feedback mechanism?

• A. Labor contractions✓
• B. Body temperature
• C. Insulin production
• D. Thyroxine release

Explanation: A feedback mechanism is a loop system wherein the system responds to a perturbation. The response may be in the same direction (as in positive feedback) or in the opposite direction (as in negative feedback). An example of positive feedback is uterine contractions during childbirth. The hormone oxytocin, made by the endocrine system, stimulates the contraction of the uterus. This produces the pain sensed by the nervous system. In response, more oxytocin is released which in turn stimulates the contractions even more. This loop of the 'pain induced from contractions stimulating the release of oxytocin, and oxytocin stimulating more contraction continues with increasing intensity' still the fetus is birthed. This is a positive feedback loop hence, Option A is correct.

Q47. Which one of the following is common to all neurons?

• A. A cell body which contains a nucleus✓
• B. Presence of Nodes of Ranvier
• C. A thick myelin sheath
• D. Presence of Schwann cells

Explanation: The cell body or soma is the main nutritional part of the cell and is concerned with the biosynthesis of materials necessary for the growth and maintenance of the neuron hence is present in all neurons.

Q48. Neurons are cells adapted for the rapid transmission of electrical impulses. To do this, they have long thin processes called:

• A. Axons✓
• B. Dendrites
• C. Myelin sheath
• D. Schwann cell

Explanation: The long thin processes that transmit neural impulses from one part to the other are called axons. Hence, Option A is correct. Dendrites are relatively short cytoplasmic extensions. Hence, Option B is rejected. Schwann cells help form the myelin sheath which is an insulating layer covering the axon externally allowing rapid neural transmission via saltatory conduction. Hence, both Option C, and Option D are incorrect.

Q49. Which of the following sections of a sarcomere does not shorten during contraction?

• A. I band
• B. H zone
• C. A band✓
• D. None of these

Explanation: Even though the 'I band' and the 'H zone' change in length, the 'A band' remains the same in length. 'A' is not the answer because the I band reduces in size. 'B' is not the answer because the H zone disappears during contraction.

Q50. The radial symmetry is found in the animals of which of the following?

• A. Protozoa
• B. Porifera
• C. Cnidaria✓
• D. All of these

Explanation: 'Radial symmetry' is the arrangement of body parts around a central axis and is only present in grade radiata. 'A' and 'B' are not the answers because both of the classes are primitive and are not diploblastic. Radial symmetry is found in the 'cnidarians' (including jellyfish, sea anemones, and coral) and 'echinoderms' (such as sea urchins, brittle stars, and sea stars).

Q51. When resources gets scarce, the population growth?

• A. Becomes fast
• B. Slows down✓
• C. Remains same
• D. None of these

Explanation: A decrease in the number of resources will lead to more competition between the individuals in a population and hence lead to the death of some of the weaker ones resulting in an overall 'decrease in the population growth'.

Q52. Which of the following is not associated with the process of respiration?

• A. Lungs
• B. Gills
• C. Bladder✓
• D. Trachea

Explanation: The bladder is not directly associated with the process of respiration. The bladder is an organ found in the urinary system of vertebrates, including humans. Its primary function is to store urine temporarily until it is expelled from the body during the process of urination. Urine is produced in the kidneys as a waste product of metabolism and has no direct involvement in the respiration process.

Q53. Which of the following is made up of an afferent pathway from a receptor and an efferent pathway to an effector?

• A. Nerve cell
• B. Reflex arc✓
• C. Receptor cells
• D. Mixed nerve

Explanation: The diagram shows a reflex arc which consists of receptor, afferent neuron, efferent neuron, and then the effector.

Q54. The types of gametes produced by two pairs of chromosomes can be?

• A. 2
• B. 4✓
• C. 6
• D. 8

Explanation: Humans have 2 pairs of chromosomes. So for each pair, there are two options available. 2C1 x 2C1= 2 x 2 = 4 When two pairs of chromosomes undergo meiosis, the different combinations of maternal and paternal chromosomes lead to four different types of gametes. This is due to the independent assortment of homologous chromosomes during meiosis I. Each homologous pair aligns independently during metaphase I, leading to a random distribution of maternal and paternal chromosomes into the resulting gametes. As a result, four different combinations of alleles are possible for each pair of chromosomes.

Q55. Which of the following statements about chordates is true?

• A. They are protostomes
• B. All chordates are vertebrates
• C. They lack a coelom
• D. Their anus forms from the blastopore✓

Explanation: Chordates are deustromes so the answer cannot be Option A. All vertebrates are chordates but not all chordates are vertebrates so the answer cannot be Option B. All chordates have a coelom so the answer cannot be Option C and their anus is formed first from blastopore so the answer is Option D.

Q56. A common polyhedral capsid shape of viruses is a?

• A. Icosahedron✓
• B. Pentagon
• C. Cube
• D. Pyramid

Explanation: Polyhedral viruses consist of nucleic acid surrounded by a polyhedral (many-sided) shell or capsid, usually in the form of an icosahedron Option B,C and D are incorrect .

Q57. Which of the following is NOT a characteristic feature of tapeworm?

• A. Each body segment has two sets of male and female reproductive organs.
• B. The digestive tract develops from endodermal cells in the embryo.✓
• C. The body can be cut into two parts, which are mirror images of each other, in one plane only.
• D. None of these

Explanation: Tapeworms do not have a digestive system and are obligate parasites, obtaining nutrients directly from their host.

Q58. HDL is synthesized in;

• A. Liver
• B. Intestine
• C. Liver and Intestine✓
• D. Adipose tissue

Explanation: The HDL particle is synthesized mainly by the liver, and also by the intestines. When excess cholesterol occurs in extra-hepatic tissues, it is picked up by HDLs by a process called reverse cholesterol transport. Option A,B and D are incorrect

Q59. In Anaerobic respiration, how much % of the energy, present within the chemical bond of glucose, is converted into ATP?

• A. 2✓
• B. 4.5
• C. 5.6
• D. 7.7

Explanation: In Anaerobic respiration only 2% of the energy present within the chemical bond of glucose is converted into ATP.

Q60. A _ is a junction between two neurons or between a motor neuron and a muscle cell:

• A. Impulse
• B. Synapse✓
• C. Axon
• D. Cleft

Explanation: Impulses are the signal that travels along the length of a nerve fiber in the form of action potentials and ends in the release of neurotransmitters. Option A is therefore incorrect. In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. It can be visualized as a gap between two neurons however, that gap isn't referred to as a synapse but rather the gap, also known as the synaptic cleft, alongside the end of the pre-synaptic neuron and the start of the post-synaptic neuron is collectively known as the synapse. Option B is hence correct. Axon also called nerve fiber, is a portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. A neuron typically has one axon that connects it with other neurons or with muscle or gland cells. You can remember A for Away. Option C is hence, incorrect. A (synaptic) cleft, as mentioned earlier is just a gap between the pre-synaptic and post-synaptic membranes. SInce this is not a junction, Option D is also incorrect.

Q61. Which one of the following represents the changes that occur in the ovary and the uterus approximately every 28 days involving ovulation with the breakdown and loss of the lining of the uterus?

• A. Ovulation
• B. Menstrual cycle✓
• C. Uterine cycle
• D. Embryo formation

Explanation: Changes that occur in females in ovary and uterus every 28 days is collectively referred to as menstrual cycle.

Q62. Which of the following diseases is sexually transmitted?

• A. Tuberculosis
• B. AIDS✓
• C. Dengue Fever
• D. Cholera

Explanation: Acquired immunodeficiency syndrome (AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight infection and disease. You can get HIV from contact with infected blood, semen, or vaginal fluids. Most people get the virus by having unprotected sex with someone who has HIV. Another common way of getting it is by sharing drug needles with someone who is infected with HIV. Hence, Option B is correct. Tuberculosis is caused by bacteria that spread from person to person through microscopic droplets released into the air. This can happen when someone with the untreated, active form of tuberculosis coughs, speaks, sneezes, spits, laughs, or sings. Hence, Option A is incorrect. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito. Then, when the infected mosquito bites another person, the virus enters that person's bloodstream and causes an infection. Hence, Option C is incorrect. A person can get cholera by drinking water or eating food contaminated with cholera bacteria. In an epidemic, the source of the contamination is usually the feces of an infected person that contaminates water or food. Hence, Option D is incorrect.

Q63. According to lvanovski, what are soluble living germs?

• A. Bacteria
• B. Viruses✓
• C. Fungi
• D. Both A and B

Explanation: According to Ivanovski, the term "soluble living germs" refers to the infectious agent responsible for causing the disease tobacco mosaic disease (TMD). Dimitri Ivanovski, a Russian botanist, conducted pioneering research in the late 19th century to investigate the cause of TMD, which affects tobacco plants.

Q64. If both the alleles are same with respect to genes, then they are called?

• A. Heterozygous
• B. Unicellular
• C. Homozygous✓
• D. None of these

Explanation: If both of the two gametes (sex cells) that fuse during fertilization carry the same form of the gene for a specific trait, the organism is said to be 'homozygous' for that trait. 'A' is not an answer because heterozygous refers to having inherited different forms of a particular gene from each parent.'B' is not the answer because the term unicellular refers to the state of a cell.

Q65. Aquatic arthropods belonging to this class breathe through gills.

• A. Insects
• B. Arachnids
• C. Crustaceans✓
• D. Arachnids and Crustaceans

Explanation: 'Aquatic arthropods' (crustaceans and the chelicerate horseshoe crabs) possess gills for respiration. Although they vary in structure and location, the gills are always outgrowths of the integument (skin) and are therefore covered by the exoskeleton, which is thin in this area and not a barrier to the exchange of gases.

Q66. As long as two species occupy different niches, there is?

• A. Competition
• B. No competition✓
• C. Gene linkage
• D. Polymorphism

Explanation: As long as two species occupy different niches there can be no competition between them.

Q67. The type of plastids found in the roots of plants are _.

• A. Chloroplasts
• B. Chromoplasts
• C. Leucoplasts✓
• D. All of these options are correct

Explanation: c) Leucoplasts:Leucoplasts are a third type of plastid found in plant cells. They are non-pigmented and play a role in storing or synthesizing various substances. There are different types of leucoplasts, including amyloplasts (which store starch), elaioplasts (which store oils and lipids), and proteinoplasts (which store proteins). These plastids are commonly found in non-photosynthetic tissues like roots, seeds, and tubers, where they assist in various storage functions.

Q68. For attachment, rabies virus binds to a

• A. Complement receptor
• B. Integrin ICAM-1
• C. Acetylcholine✓
• D. Epidermal growth factor

Explanation: There is convincing in vitro evidence that the muscular form of the nicotinic acetylcholine receptor (nAChR), the neuronal cell adhesion molecule (NCAM), and the p75 neurotrophin receptor (p75NTR) bind rabies virus and facilitate rabies virus entry into cells. Option A,B and D are incorrect

Q69. Which of these is a characteristic of prokaryotic cells?

• A. Absence of membrane bound cell organelles
• B. Presence of 70S ribosomes
• C. Both Options A and B are correct✓
• D. None of these

Explanation: Prokaryotic cells lack a nucleus, have no membrane-bound organelles, and have 70S ribosomes.

Q70. Which of the following hormones of the pituitary gland regulates the menstrual cycle?

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

Explanation: Four hormones are primarily active in the menstrual cycle namely; FSH: Secreted by the anterior pituitary gland. In women, FSH helps control the menstrual cycle and stimulates the growth of eggs in the ovaries. LH: Secreted by the anterior pituitary gland. It also triggers the release of an egg from the ovary in the process known as 'ovulation'. (Option C is therefore correct since both; FSH and LH are produced by the pituitary gland)Estrogen: The ovaries, which produce the eggs, are the main source of estrogen from your body. In females, it helps to develop and maintain both the reproductive system and female characteristics, such as the breasts and pubic hair. Estrogen causes the uterine lining to grow and thicken to prepare the uterus for pregnancy. Progesterone: The corpus luteum in the ovaries, and the placenta, after the embedding of the zygote in the uterus lining, tend to release progesterone. The hormone prepares the endometrium lining to receive and nourish a fertilized egg. If pregnancy does not occur, estrogen and progesterone levels decrease. The decrease in progesterone triggers menstruation or shedding of the lining. Once the lining is completely shed, a new menstrual cycle begins.

Q71. Haemophilia occurs because of:

• A. Mutation in an autosome
• B. Mutation of Y-chromosome
• C. Mutation of X-chromosome✓
• D. Deficiency of iron

Explanation: Hemophilia is a bleeding disorder that slows the blood clotting process. Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, it is very rare for females to have hemophilia. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.So, the correct answer is 'Mutation of X-chromosome'.

Q72. Which traits are most likely to affect men than women?

• A. X linked recessive✓
• B. X linked dominant
• C. Autosomal dominant
• D. Autosomal recessive

Explanation: Every cell in the human body has 23 pairs of chromosomes. One of these pairs is made up of 2 sex chromosomes. These are called X and Y chromosomes. One of these is inherited from the mother and the other from the father. Females have 2 X chromosomes, while males have 1 X and 1 Y chromosome. In females, the normal, unchanged, or healthy gene can override a recessive mutation so the disorder is suppressed. Disorders linked to X-linked recessive mutations usually only happen in females when they have 2 copies of the recessive mutation (1 on each X chromosome). In this case, there's no dominant "healthy" gene to override it. But, in males, there's only 1 X chromosome and if it has the recessive mutation, they will have the disorder. Recessive X-linked disorders tend to be more common in males because it's less likely that a female will get 2 copies of the recessive mutation. In females, dominant X-linked mutations will always cause the disorder. This is because the mutated gene takes over or overrides the genes on the healthy X chromosome. In males, remember, there's only 1 X chromosome and if it has the dominant mutation, they'll have the disorder. Mutations on autosomal chromosomes (22 pairs of chromosomes other than the sex chromosomes) will have an equal effect on both males and females.

Q73. Which cells secrete flexible, elastic, non-living matrix collagen that surrounds the chondrocytes?

• A. Osteocytes
• B. Osteoclasts
• C. Chondrocytes✓
• D. Osteoblasts

Explanation: 'Chondrocytes' are the first chondroblast cells that produce the collagen extracellular matrix (ECM) and then get caught in the matrix. Options A, B, and D are wrong because all three cells are related to bone whereas 'option C' is related to cartilage.

Q74. Salamander belongs to which of the following class?

• A. Pisces
• B. Aves
• C. Reptiles
• D. Amphibians✓

Explanation: 'Salamanders' are a type of amphibian; they have moist skin and are usually found in damp habitats near or in water. Salamanders are more closely related to frogs despite how different frogs and salamanders look.

Q75. Which of the following statement was not explained by Darwin's theory?

• A. The significance of minute variations
• B. Presence of vestigeal or useless organs
• C. The presence of over specialized organs
• D. All of the above✓

Explanation: 'Darwin's theory' was based on variations, struggle, natural selection and differential reproduction. Thus, Darwin maintained that living organisms show variations and the variant best suited is selected by nature to 'reproduce'. Thus, vestigial or over specialized organs are not expected. Vestigial organs might arise by progressive disuse and over specialized organs by progressive use. Both of these are not a Darwinian view. Darwin's view is that if something is useful it will be selected to be passed on to the next generation and that's it. Not that, that organ will become overspecialized or vestigial, if not required. In the same way, minute variations, which do not confer any major advantage to the organism in a particular environment are useless and will not affect evolutionary process.

Q76. Which statement correctly outlines some of the main events in photosynthesis?

• A. A 5C carbohydrate accepts carbon dioxide and is then reduced by NADPH derived from photosynthesis
• B. A 3Ccarbohydrate is regenerated and reduced by hydrogen molecules derived from photophosphorylation
• C. Photolysis uses light to produce reduced NADP and oxygen which are used to reduce a 3Ccarbohydrate✓
• D. Photolysis produces NADPH and ATP which are used to reduce a 5C cartediadrate

Explanation: "The explanation for this question will be added soon!".

Q77. In photosynthesis dark reaction, is called so because:

• A. It occurs in dark
• B. It does not require light energy✓
• C. It cannot occur during daytime
• D. It occurs more rapidly at night

Explanation: "The explanation for this question will be added soon!".

Q78. In uncompetitive inhibition, the inhibitor binds with:

• A. Enzyme
• B. Substrate
• C. ES-complex✓
• D. All of these options are correct

Explanation: Uncompetitive inhibition occurs when an inhibitor binds to an allosteric site of a enzyme, but only when the substrate is already bound to the active site. In other words, an uncompetitive inhibitor can only bind to the enzyme-substrate complex.

Q79. Sycon is an example of:

• A. Platyhelminthes
• B. Annelids
• C. Protozoa
• D. Porifera✓

Explanation: Sycon is an example of Porifera. Porifera is a phylum of animals that are also known as sponges. Sponges are simple animals that do not have a body cavity or organs. They are filter feeders, meaning that they obtain their food by filtering water through their bodies.

Q80. Out of 31 pairs of spinal nerves, how many are pairs of coccygeal nerves?

• A. 1✓
• B. 12
• C. 15
• D. 10

Explanation: In total, there are 31 pairs of spinal nerves grouped regionally by spinal region. More specifically, there are eight cervical nerve pairs (C1-C8), twelve thoracic nerve pairs (T1-T12), five lumbar nerve pairs (L1-L5), 5 sacral (S1-S5), and a single coccygeal nerve pair. Option B,C and D are incorrect

Q81. What is the major cell infected by the AIDS HIV Virus?

• A. Lymphocytes
• B. Cancer cells
• C. Stem cells
• D. T lymphocytes✓

Explanation: HIV primarily targets a type of cell in the immune system called the CD4+ T cell. However, many types of these cells exist, and they are not all equally susceptible to infection by HIV HIV also affects central nervous system Option A,B and C are incorrect

Q82. The hinge joint and ball and socket joints are the types of

• A. Freely movable joints✓
• B. Slightly movable joints
• C. Immovable joints
• D. None of these

Explanation: The hinge joint shows movement in one plane while the ball and socket joints allow movement in three planes. Both of them are freely moveable joints since they allow large movements.

Q83. _ alleles both have an effect on the phenotype of a heterozygous organism:

• A. Dominant
• B. Recessive
• C. Co-dominant✓
• D. Multiple

Explanation: In a Co-dominant scenario, the two different alleles of the gene contributing to a particular characteristic would express themselves in a collaborative manner, producing a phenotype that is a combination of the two different phenotypes coded by the respective alleles.

Q84. When both the alleles of a gene pair are same, the organism is said to be:

• A. Heterozygous
• B. Genotype
• C. Homozygous✓
• D. Phenotype

Explanation: An allele is one of two, or more, forms of a given gene variant. Each person has at least two alleles for a specific gene. If they are the same then the organism is called Homozygous for that gene. (Option B is correct) And if they are different, they are called heterozygous for that allele. A genotype is an organism's set of heritable genes that can be passed down from parents to offspring. A phenotype is an individual's observable traits, such as height, eye color, and blood type.

Q85. The reduction of nitrile produced a compound of formula C3H7NH2. Which one of the following compounds would be produced if the same nitrile was hydrolyzed by heating with dilute hydrochloric acid?

• A. CH3CONH2
• B. CH3CH2NH2
• C. (CH3)2CHCO2H
• D. CH3CH2CO2H✓
• E. CH3CH2OH

Explanation: The hydrolysis of nitrile produces carboxylic acid. Since the number of carbons given in our question is 3 so the correct answer should be a carboxylic acid with 3 carbons and that is option D. A and B are amines, hence wrong. C is wrong because it has extra carbon. E is wrong because it is alcohol.

Q86. Which of the following reaction has greater Kp than Kc?

• A. 2NO + Cl2 <-> 2NOCl
• B. 2SO2 + O2 <-> 2SO3
• C. 2NOCl <-> 2NO + Cl2✓
• D. N2 + 3H2 <-> 2NH3

Explanation: When the volume of products is greater than the volume of reactants, then Kp> Kc. From the options above, only Option C has more volume of gases at the product side as compared to the reactant side. We concluded this from the mole ratio of the equation which is 3 on the product side against 2 on the reactant side.

Q87. The equation N2(g) + 3H2(g) ⇋ 2NH3(g) represents:

• A. Contact process
• B. Haber’s process✓
• C. Solvay process
• D. Avogadro’s Law

Explanation: The Haber process combines nitrogen from the air with hydrogen derived mainly from natural gas (methane) into ammonia. The reaction is reversible and the production of ammonia is exothermic. with ΔH=−92.4kJ/mol. Thus the equation in the question suits the above definition: N2(g) + 3H2(g) ⇋ 2NH3(g)

Q88. The relationship between quantum number n and l is:

• A. n = l - 1
• B. l = n - 2
• C. l = n - 1✓
• D. n = l - 2

Explanation: The principal quantum number, n, describes the energy of an electron and the most probable distance of the electron from the nucleus. In other words, it refers to the size of the orbital and the energy level the electron placed in it. The number of subshells or I describes the shape of the orbital.

Q89. Purification of table salt (NaCl) by passing HCl gas through its saturated aqueous solution is an example of:

• A. Law of mass action
• B. Hess’s law
• C. Common ion effect✓
• D. Henry’s law

Explanation: In saturated solution of NaCl,equillibrium is established between ions and unionised NaCl. NaCl ⇌ Na+ + Cl- When HCl gas is passed through a saturated solution of NaCl, it is completely dissociated to form H+ and Cl- ions. HCl —>H+ + Cl- Cl- ion is common to both electrolytes, hence Cl- ion concentration in solution increases. According to Le-chatelier’s principle, the position of the equilibrium gets shifted to the left side. Hence the ionization of NaCl gets suppressed and the deposition of NaCl takes place.

Q90. How will the equilibrium of the following reaction be affected if additional nitrogen is added? N2(g) + 3H2(g) ⇌ 2NH3(g)

• A. It will be shifted to the right.✓
• B. It will be shifted to the left.
• C. it will be unaffected.
• D. The effect on the equilibrium cannot be determined without more information.
• E. More NH3 will be produced.

Explanation: If N2 is added the equilibrium will be shifted to the right side as N2 is the reactant. According to Le Chatelier, increasing the concentration of the reactants favor the forward reaction.

Q91. In which of the following will water evaporate earlier?

• A. Cup
• B. Saucepan✓
• C. Glass
• D. Small bowl

Explanation: The rate of water evaporation depends on various factors such as the surface area exposed to air, temperature, humidity, and airflow. In general, water will evaporate more quickly in conditions where these factors promote evaporation. If we assume that the initial conditions (temperature, humidity, etc.) are the same for all containers, then the primary factor influencing the rate of evaporation would be the surface area exposed to air. Larger surface areas allow for more water molecules to be in contact with the air, promoting faster evaporation. A wide saucepan typically has a larger surface area compared to a cup, glass, or small bowl. Therefore, under similar conditions, water is likely to evaporate earlier from a saucepan than from the other containers.

Q92. Different kinds of atoms of the same element are called isotope having different _but same _ properties.

• A. Physical, atomic
• B. Physical, chemical✓
• C. Chemical, physical
• D. Chemical, atomic

Explanation: Isotopes of an element have the same atomic number and therefore 'similar chemical properties'. Their physical properties may be 'different'.

Q93. The order of reaction for which half-life is inversely proportional to the concentration of reaction is?

• A. Second Order✓
• B. Zero Order
• C. First Order
• D. Third Order

Explanation: A second-order reaction is a type of chemical reaction that depends on the concentrations of a one second-order reactant or two first-order reactants. This reaction proceeds at a rate proportional to the square of the concentration of one reactant, or the product of the concentrations of two reactants.

Q94. The unit used to express the relative atomic mass is called

• A. Gram unit
• B. Avogadro's number
• C. Atomic mass
• D. Atomic mass unit✓

Explanation: One atomic mass unit (1u) is a mass unit equal to exactly one-twelfth (1/12th) the mass of one atom of carbon-12 isotope, which is the scale used to compare atomic masses. So, the unit used to express relative atomic mass is amu. Thus, option D is correct.

Q95. Which of the following properties does not belong to Gases?

• A. Indefinite volume
• B. Indefinite shape
• C. Low density
• D. Strong interactions✓

Explanation: Strong interactions as gases have weak interactions since the particles move quickly in random motion and move far apart from each other which results in weak intermolecular forces of attraction.

Q96. Primary Alcohol is produced by reactions of Grignard's reagent with _ followed by hydrolysis in an acidic medium.

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

Explanation: The Grignard Reaction is the addition of an organomagnesium halide (Grignard reagent) to a ketone or aldehyde, to form tertiary or secondary alcohol, respectively. The reaction with formaldehyde leads to primary alcohol.

Q97. Which of the following is TRUE regarding Methyl Alcohol?

• A. It is a colorless, volatile, thin liquid with specific gravity 0.796 at 15°C.✓
• B. It is used for low-temperature thermometers and as a fuel substitute.
• C. It is extensively used in the formation of different beverages.
• D. It is used as a base for perfumes
• E. It is used as an antiseptic and disinfectant

Explanation: Properties of Methyl Alcohol include: -Colourless -Volatile -Thin liquid with a specific gravity of 0.796 at 15°C. Methyl alcohol is not an effective sanitizer. Since it is toxic and can readily be absorbed under the skin it is never used as a perfume. For the same reason not used to make beverages. It is not used in thermometers. Options B and C are the characteristics of Ethanol. Option D represents esters. Option E represents Phenol.

Q98. Which type of isomerism depends on the distribution of carbon atoms on each side of the functional group?

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

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

Q99. Which one of the following molecules has the shortest distance of carbon atoms?

• A. CH3 - CH3
• B. CH2 = CH2
• C. CH ≡ CH✓
• D. CH3 - CH2 - CH3
• E. CH2 = CH2 - CH3

Explanation: The more the number of bonds the lesser will be the bond distance. Since the CH ≡ CH has the most number of bonds between two carbon atoms, it has the shortest bond length.

Q100. Which pair has 1 electron in it’s ‘s’ orbital?

• A. Li & Fe
• B. Na & Cr✓
• C. K & Mn
• D. H & He

Explanation: Na electron configuration is 1s2 2s2 2p6 3s1.Cr electron configuration is [Ar] 3d⁵ 4s¹.

Q101. A reaction with a tendency of occurring in forward and backward direction simultaneously is termed as

• A. Irreversible
• B. Unidirectional
• C. Multidirectional
• D. Reversible✓

Explanation: These two reactions are occurring simultaneously, which means that the reactants are reacting to yield the products, as the products are reacting to produce the reactants. This process continues over and over again, representing a reversible reaction.

Q102. Rate constant is denoted by?

• A. k✓
• B. kv
• C. kf
• D. ks

Explanation: The rate constant in chemical reactions is indeed denoted by the symbol "k". It represents the proportionality constant that relates the rate of reaction to the concentrations of the reactants.

Q103. Structure of ice is similar to which of the following?

• A. Liquid water
• B. Diamond✓
• C. Graphite
• D. Sucrose

Explanation: Correct option is B Crystalline Structure of Ice resembles diamond. There are two closely related variants of ice I: hexagonal ice Ih, which has hexagonal symmetry, and cubic ice Ic, which has a crystal structure similar to diamond. Ice Ih is the normal form of ice; ice Ic is formed by depositing vapor at very low temperatures (below 140°K).

Q104. Which of the following is an assumption of the kinetic model of an ideal gas?

• A. Gas is at high pressure
• B. Collision between particles are elastic✓
• C. There are weak forces of attraction between particles in gas
• D. Total energy of particles is proportional to the temperature

Explanation: Correct option is B The five main postulates of the KMT are as follows: (1) the particles in a gas are in constant, random motion (2) the combined volume of the particles is negligible (3) the particles exert no forces on one another (4) any collisions between the particles are completely elastic (5) the average kinetic energy of the particles is proportional to the temperature in kelvins. Postulate are given below

Q105. Which of the following exerts the lowest vapour pressure?

• A. Chloroform
• B. Methanol
• C. Water✓
• D. Ethanol

Explanation: The stronger the intermolecular forces, the lower the vapor pressure. Water has the strongest forces amongst these options (4 H-bonds), hence it will have the lowest vapor pressure.

Q106. Linear combination of atomic orbitals (LCAO) results in the formation of:

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

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

Q107. The raindrop acquires a spherical shape and ink spread over blotting paper due to:

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

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

Q108. Ethanol, when reacted with PCI5 , gave A, POCl3, and HCI. A reacts with AgNO2 to form B and AgCl. A and B are respectively:

• A. C2H5Cl and C2H5OC2H5
• B. C2H6 and C2H5OC2H5
• C. C2H5Cl and C2H5NO2✓
• D. C2H6 and C2H5NO2
• E. C2H6 and C2H6NO

Explanation: C2H5Cl and C2H5NO2 are the products of the following reaction equation: C2H5OH + PCl5 -----> C2H5Cl + POCl3 + HCl C2H5Cl + AgNO2 -----> C2H5NO2 + AgCl

Q109. The transition element which does not show variable valency is:

• A. Cu
• B. Sc
• C. Zn✓
• D. Cr

Explanation: Zn has its d orbital completely filled thus it cannot be called a transition element and cannot possess the properties shown by the transition elements. Hence, it does not show variable valency.

Q110. During oxidation process, oxidation number of an element:

• A. Decreases
• B. Increases✓
• C. Remains constant
• D. Both decreases and increases

Explanation: A loss of negatively-charged electrons corresponds to an increase in oxidation number, while a gain of electrons corresponds to a decrease in oxidation number. Therefore, the element or ion that is oxidized undergoes an increase in oxidation number.

Q111. Which of the following has lowest e/m ratio?

• A. Li+2
• B. H+
• C. He+
• D. Be✓

Explanation: The charge to mass ratio is called the e/m ratio. e/m ratio is a physical quantity, widely used in the electrodynamics of charged particles. All we have to do in this scenario is divide the net charge of the species given in the options by their respective relative atomic mass. As Be is practically neutral, it has no net charge or a charge of zero making its e/m zero as well; the lowest out of the options provided.e/m value of cathode ray particle is (1.758820088±39)×1011 [C/kg]

Q112. Prussian blue is:

• A. K2Fe[FeCN6]
• B. K4[FeCN6]
• C. Fe4[Fe(CN)6] 3xH2O✓
• D. K3FeCN6

Explanation: This is the following solution:

Q113. Variable valency is generally exhibited by:

• A. Normal elements
• B. Transition elements✓
• C. Metallic elements
• D. None of them

Explanation: Transition elements show variable oxidation states because: 1. the energy difference between 3d and 4s orbitals is very small. 2. electrons of both 3d and 4s orbitals participate in bond formation (however, electrons are first lost from the 4s orbital).

Q114. Which type of movement is shown by the atoms of the solid?

• A. Translational motion
• B. Vibrational motion✓
• C. Rotational motion
• D. Linear motion

Explanation: Correct option is B Solid has a fixed shape and a fixed volume because the particles can move only a little. The particles vibrate back and forth but remain in their fixed positions. As a solid is heated, the particles vibrate faster and faster until they have enough energy to break away from their fixed positions.

Q115. The rate of diffusion of liquids is _ than gases.

• A. Lower✓
• B. Higher
• C. Equal to
• D. All of these options are correct

Explanation: Diffusion is the intermixing (movement) of molecules. When looking at diffusion you must look at two factors: forces of attraction and kinetic energy of molecules. Liquids have a stronger force of attraction than gases, and liquids have less KE than gases. This is because gas particles are further apart compared to liquid particles and move faster. This makes liquids have a lower rate of diffusion than gases.

Q116. Real gas is converted to ideal gas at:

• A. Low temperature, high pressure
• B. High temperature, high pressure
• C. Low temperature, low pressure
• D. High temperature, low pressure✓

Explanation: At high temperatures and low pressure, molecules of a gas are far apart, with minimal forces of attraction between them. This causes real gases to behave much like an ideal gas.

Q117. Ethyl iodide and n-propyl iodide are allowed to undergo Wurtz reaction. The alkane which will not be obtained in this reaction is:

• A. butane
• B. propane✓
• C. pentane
• D. hexane

Explanation: Correct option is B.

Q118. During condensation polymerization, two monomers may be joined by the removal of a molecule of:

• A. Carbon Dioxide
• B. Hydrogen
• C. Oxygen
• D. Water✓
• E. None of these options

Explanation: During condensation polymerization, two molecules are joined together with the removal of H2O molecules.

Q119. Harmful and undesirable reaction of a metal when exposed to the atmosphere or any chemical agent is known as:

• A. Allotropy
• B. Electroplating
• C. Collision
• D. Cracking
• E. Corrosion✓

Explanation: The harmful and desirable reaction which occurs due to oxidation of the metal exposed to the surrounding air is called corrosion.

Q120. Purification of bauxite whose major impurity Is silica (SiO2) is carried out through:

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

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

Q121. Sigma bond is formed by:

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

Explanation: Sigma bond is formed by head-on overlapping of the two orbitals, as shown below:

Q122. The isomers must have the same:

• A. Physical properties
• B. Molecular Formula✓
• C. Structural Formula
• D. Chemical properties
• E. Both Molecular and Structural formula

Explanation: Isomers have the same molecular formula but different structures.

Q123. CH3CH2CH2COCH3 is the functional isomer of:

• A. CH3CH2CH2CH2CHO✓
• B. CH3CH2CH2CH2OH
• C. CH3CH2COCH2CH3
• D. CH3 - (CH)2 COCH2CH3

Explanation: CH3CH2CH2COCH3 and CH3CH2CH2CH2CHO have the same number of atoms for the constituent elements, Carbon, Oxygen, and Hydrogen. However, the second requirement of a 'Functional Isomer' is that the functional groups, of the two isomers, must be different and since, in this case, we have a ketone functional group and an aldehyde functional, both compounds can be positively termed as 'Functional Isomers' of each other.Thus, option A is correct.

Q124. IUPAC name of this is (CH3)2 - CH - CH (C2H5) - C(CH3)3

• A. 3-ethyl-2, 2, 4-trimethyl pentane✓
• B. 4-ethyl-2, 2, 4-trimethyl pentane
• C. 5-ethyl-2, 2, 4-trimethyl pentane
• D. 2-ethyl-2, 2, 4-trimethyl pentane
• E. 1-ethyl-2, 2, 4-trimethyl pentane

Explanation: The IUPAC name for the given compound (CH3)2-CH-CH(C2H5)-C(CH3)3 is "3-ethyl-2,2,4-trimethylpentane." Here's how the name is derived: 1. Identify the longest continuous carbon chain, which in this case is a five-carbon chain. 2. Number the carbon chain to give the substituents the lowest possible locants. In this case, we start numbering from the end nearest to the ethyl group, so the ethyl group is located on carbon 3. 3. Assign substituent names and locants. The methyl groups attached to carbon 2 and carbon 4 are called "2,2-dimethyl" and "2,4-dimethyl," respectively. The ethyl group attached to carbon 3 is named "ethyl." 4. Combine all the parts to form the complete IUPAC name: "3-ethyl-2,2,4-trimethylpentane." Therefore, the compound (CH3)2-CH-CH(C2H5)-C(CH3)3 is named 3-ethyl-2,2,4-trimethylpentane.

Q125. Which of the following carboxylic acids will be the most acidic?

• A. CH3CHClCH2COOH
• B. CH3CH2CCl2COOH✓
• C. CH3CH2CHClCOOH
• D. CH3CH2CH2COOH

Explanation: The acidity of carboxylic acids is significantly increased by the presence of highly electronegative functional groups. Their electron-withdrawing effect increases the stability of the carboxylate anion, favoring proton dissociation. This effect increases as the number of electronegative groups on the chain increases, and it also increases as the distance between the acid functionality and the electronegative group decreases. This answer has two halogens bound to it, at a smaller distance from the carboxyl group compared to the other answers.

Q126. Which of the following cannot be used to convert butanoic acid to butanoyl chloride?

• A. PCl3
• B. PCl5
• C. CCl4✓
• D. SOCl2

Explanation: PCl3, PCl5, and SOCl2 can be used to add Cl atoms in place of OH group. CCl4 is a carbon tetrachloride which cannot be used for this purpose.

Q127. Phenylmethyl ketone can be converted into ethyl benzene in one step by using:

• A. LiAlH4
• B. Zn(Hg)-HCl✓
• C. NaBH4
• D. CH3MgI

Explanation: The reaction is Clemmensen reduction. The reaction of aldehydes and ketones with zinc amalgam (Zn/Hg alloy) in concentrated hydrochloric acid, which reduces the aldehyde or ketone to a hydrocarbon, is called Clemmensen reduction.

Q128. What is the product of both fermentation reactions and fractional distillation:

• A. An ester
• B. An acid
• C. An alcohol✓
• D. A soap
• E. A base

Explanation: Ethanol (alcohol) can be produced by fermentation and concentrated using fractional distillation.

Q129. Which of the following is not a nucleophile?

• A. NH3
• B. HO
• C. HC = CH
• D. Br2✓

Explanation: The electron rich part of the double bond causes a dipole to form meaning that bromine becomes electron deficient and therefore becomes the electrophile (hence electrophillic addition) hence the answer is D. Rest of the options are incorrect as they have lone pair of electrons or an electron rich double bond (in case of alkenes) which makes them nucleophiles.

Q130. The general formula for an aldehyde is:

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

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

Q131. The oxidation state of “S’ in the (S2O3)-2 is:

• A. +4
• B. +6
• C. -2
• D. +2✓

Explanation: Let the Oxidation number of Sulfur in S2O32- be x. Thus; 2x+(-2 x 3)= -2 2x - 6= -2 2x= -2+6 2x=4 x=4\2 x=2 So, the oxidation state of sulfur is +2

Q132. The common oxidation number of halogens is:

• A. -1✓
• B. +1
• C. -2
• D. 0

Explanation: The most common oxidation state of halogens is -1. Halogens are the most electronegative elements of the periodic table. Their outer electron configuration is ns2, np5. If chlorine, for example, gains one more electron, the outer p orbitals are completely filled (resulting in a full octet). Since halogens are electronegative, they can easily remove an electron from nearby atoms to add into their own valence p orbital achieving a full octet.

Q133. Which of the following will not undergo aldol condensation?

• A. Acetaldehyde
• B. Propanaldehyde
• C. Formaldehyde✓
• D. Trideuteroacetaldehyde

Explanation: The aldehydes that have alpha hydrogen atoms undergo aldol condensation reaction

Q134. Alkanes having five to seventeen carbon atoms per molecule are:

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

Explanation: Following are the state of alkanes with given carbon numbers:C1-C4=GasesC5-C17=LiquidsC18+=Solids.

Q135. Which pair of ions have five unpaired d-electrons?

• A. Fe+2 and Mn+2
• B. Fe+2 and Mn+3
• C. Fe+3 and Mn+3
• D. Fe+3 and Mn+2✓

Explanation: Fe+3 has five unpaired d-electrons, while Mn+2 also has five unpaired d-electrons. Therefore, option D is correct.

Q136. Which of the following has the least ionization potential?

• A. He
• B. Li✓
• C. Zn
• D. N

Explanation: Lithium is an alkali metal, and alkali metals have very low ionization potentials due to their single valence electron and large atomic size. Lithium requires the least amount of energy to remove its valence electron.

Q137. Power developed by a person on eating 100g of ice per minute is (Latent heat of ice is 80 cal/g):

• A. 130 W
• B. 560 cal/sec
• C. 560 J/sec✓
• D. none of these

Explanation: A mass of ice eaten by the man per second. m =100/60=5/3 g/s Latent heat of ice, L = 80 cal/g. Therefore, energy required per second by the man in eating the ice, i.e., power developed by the man. = mL =5/3 x 80 cal/s 3 =5x80/3x4.2J/s=560W

Q138. A block hangs freely from the end of a spring. A boy then slowly pushes the block upwards so that the spring becomes strain free. The gain in gravitational potential energy of the block during this process is equal to:

• A. work done by the boy against the gravitational force acting on the block
• B. loss of energy stored in the spring minus the work done by the tension in the spring
• C. work done on the block by the boy plus the loss of energy stored in the spring✓
• D. work done on the block by the boy minus the work done by the tension in the spring

Explanation: Let xo be the initial extension of the spring. Then the initial energy stored in the spring is: ½kxo2 The gain in gravitational potential energy: mgh = mgxo The work done increases the gravitational potential energy and decreases the spring’s potential energy. The total energy gained = gain in the gravitational potential energy - loss in spring’s potential energy. Therefore, work done by the boy (wb) = gain in the gravitational potential energy - loss in spring’s potential From here you can see that the gain in the gravitational potential energy of the block = work done by the boy + loss in the spring’s potential energy. Therefore, option C is the correct one.

Q139. If we are standing in a bus and the driver applies a brake then we feel:

• A. A pseudo force pushes backwards
• B. A pseudo force pushes forwards✓
• C. A real force pushes backwards
• D. A real force pushes forwards

Explanation: A pseudo force (also called a fictitious force, inertial force, or d’Alembert force) is an apparent force that acts on all masses whose motion is described using a non-inertial frame of reference, such as a rotating reference frame. Pseudo force comes into effect when the frame of reference has started acceleration compared to a non-accelerating frame.

Q140. The slope of displacement-time graph has the unit:

• A. m
• B. s
• C. m/s²
• D. m/s✓

Explanation: The slope of a displacement-time graph is given by:Δy/Δx = Δs/Δt, which is equal to velocity. Hence, the correct answer is m/s.Provided below, is an example where Δs, i.e. change in displacement, is given as 17.5 m, and Δt, i.e. change in time, is given as 5 seconds. The above formula is applied to find velocity, by finding the value of the slope.

Q141. On a planet, a vertically-launched projectile takes 12.5 s to return to its starting position. The projectile gains a maximum height of 170 m. The planet does not have an atmosphere. What is the acceleration of free fall on this planet?

• A. 2.2 m s−2
• B. 8.7 m s−2✓
• C. 27 m s−2
• D. 54 m s−2

Explanation: Explanation is given below:

Q142. If a wave can be polarized, it means, it is:

• A. Longitudinal wave
• B. Stationary wave
• C. Superimposed wave
• D. Transverse wave✓

Explanation: Only transverse waves can be polarised .Longitudinal waves cannot be polarised.Transverse: vibrations perpendicular to the direction of travel of the wave .Longitudinal: vibrations parallel to the direction of travel of the wave.Sound waves are longitudinal so they cannot be polarised.Polarised: the wave vibrations occur in one plane onlyUnpolarised: the wave vibrations occur in all planes perpendicular to the direction of travel.The reason that only transverse waves can be polarised is that their vibrations can potentially occur in all directions perpendicular to the direction of travel. It is therefore possible to confine the vibrations to a single plane.Or put another way an unpolarised transverse wave is a 3D shape, it is therefore possible to confine it to a 2D shape (a plane). The vibrations of a longitudinal wave occur along a single line, it is therefore not possible to confine that to a plane, i.e. a 1D shape cannot be confined within a 2D shape. Similarly, Stationary waves and superimposed waves can not be polarised as they are along a single line.VIDEO EXPLANATION

Q143. If the body is rotating with uniform angular velocity, then its torque is:

• A. Zero✓
• B. 90
• C. 1
• D. -1

Explanation: A body moving with uniform angular velocity is having zero Angular acceleration so since torque = force * moment arm (where F=ma and a here is zero as object s not accelerating. ) so F=0 So T=0Torque is the moment of force about a body. T = F . rAngular velocity = w = d z /dt Linear velocity = v = rwlinear acceleration=a = r .[ d w/ dt ]F = ma = mr [ dw/dt]T = F.r = mr^2 [dw/dt] , mr^2 = I , the moment of inertiaT = I . [dw/dt]Now if w = angular velocity is a constant , then dw/dt = 0So that T = I[0] =0

Q144. The angular velocity of the minute hand of a clock is

• A. 2π/60rads-1
• B. π/24rads-1
• C. 2π/3600rads-1✓
• D. π/3600rads-1

Explanation: Explanation is given below:

Q145. When a body is whirled in a horizontal circle by means of a string the centripetal force is supplied by

• A. Mass of a body
• B. Velocity of body
• C. The tension in the string✓
• D. Centripetal acceleration

Explanation: Tension is the only force that provides the centripetal force in this case.

Q146. The body of a car is supported by four springs each of constant 2000 Nm-1. What will be the value of spring constant for this combination of springs?

• A. 2000 Nm-1
• B. 600 Nm-1
• C. 8000 Nm-1✓
• D. 4000 Nm-1

Explanation: The effective spring constant of multiple springs acting in parallel is equal to the sum of each individual spring constant. Because all spings in parallel must deform equally, the force required to deform the parallel springs will be equal to the sum of forces to deform each individual spring by the same amount.

Q147. The oscillating object overshoots the rest position due to:

• A. Restoring force
• B. Inertia✓
• C. Gravitational potential energy
• D. Elastic potential energy

Explanation: To get oscillations, a body is pulled away from its resting or equilibrium position and then released. The body oscillates due to a restoring force. Under the action of this restoring force, the body accelerates and overshoots the rest position due to inertia.

Q148. When an ideal gas of constant mass is heated in a container of fixed volume, what is the reason for the increase in pressure of the gas?

• A. The number of molecules per unit volume increases
• B. The molecules occupy greater volume of the container
• C. The average force per impact at the container wall increases✓
• D. The molecules collide with each other with greater force

Explanation: The number of molecules per unit volume cannot increase because as specified by the question statement, the mass is constant. Moreover, molecules can only occupy the volume of the container. Since the volume of the container is fixed, they can't occupy a greater volume. Molecules do collide with each other with greater force but that is not the reason for the increase in the pressure of the gas. Molecules of gases are contiually colliding with each other and with the walls of the container. When a molecule collides with the wall, it exerts a small force on the wall. The pressure exerted by the gas is due to the sum of all these collision forces with the wall. As heat is supplied, molecules gain greater Kinetic Energy and collide with the wall harder and faster.

Q149. The angular measurement is known as _ measurement

• A. parameter
• B. area
• C. circumference✓
• D. all of these

Explanation: As θ= Angular displacement or measurement Explanation for this question will be added soon.As θ= Angular displacement or measurement S= arc length or circumference r= radius of circle Since θ= S/r Hence angular displacement is related to circumference or arc length as rhey are directly related.

Q150. Acceleration in the simple pendulum is always _ to displacement.

• A. Inversely proportional
• B. Directly proportional
• C. Acting positive✓
• D. Independent

Explanation: In terms of directly proportional and sign, the acceleration in a simple pendulum is directly proportional to the displacement but has opposite signs. When a simple pendulum is displaced from its equilibrium position, the acceleration is directly proportional to the displacement. This means that as the displacement of the pendulum bob increases, the magnitude of the acceleration also increases proportionally. However, the sign of the acceleration is opposite to the displacement. When the pendulum bob is displaced to one side, the acceleration acts in the opposite direction, towards the center of the oscillation. As the pendulum bob swings back and forth, the acceleration continuously changes its direction, always directed towards the center of the oscillation and opposite to the displacement. For example, if the pendulum bob is displaced to the right, the acceleration will be directed towards the left. If the pendulum bob is displaced to the left, the acceleration will be directed towards the right. So, in summary, the acceleration in a simple pendulum is directly proportional to the displacement but has an opposite sign.

Q151. Velocity of sound in air is 332m/s. Velocity of sound in vacuum would be:

• A. More than 332m/s
• B. Less than 332m/s
• C. 332m/s
• D. Zero✓

Explanation: Sound waves are longitudinal waves and they need a medium to travel. Thus, they cannot travel in vaccum.

Q152. The diagram shows a wire, carrying an electronic current I, placed between the poles of a magnet. In which direction does the force on the wire act?

• A. Into the paper✓
• B. Towards the N pole of the magnet
• C. Out of the paper
• D. Towards the S pole of the magnet

Explanation: F=I(LxB) The direction of L is in the direction of the current. The direction of the magnetic force F is the right angle to the plane containing L and B. It is given by right-hand rule of the cross product (into the paper).

Q153. The ratio of the number of turns in primary and secondary coils of a transformer is 1:20. The ratio of the currents in the primary and secondary will be

• A. 1:20
• B. 20:1✓
• C. 1:400
• D. 400:1

Explanation: Explanation is giving below:

Q154. The change in resistance of metallic conductor at temperature below 0 degrees is:

• A. Non-linear
• B. Curve
• C. Linear✓
• D. Curvilinear

Explanation: The resistance increases as the temperature of the metallic conductor increases. The graph between resistance and temperature is linear for both increasing and decreasing temperatures.

Q155. Some ice, at its melting point, is added to m kg of water at the initial temperature of 290K. The ice melts completely and the final temperature of the water is 273K. If c is the specific heat capacity of the water and L is the latent heat of fusion of ice, what is the minimum mass of ice that is required?

• A. 17mc/L✓
• B. L/17mc
• C. 17m/Lc
• D. 290m/Lc

Explanation: Refer to the working below:

Q156. The force between two charges Q and q, separated by a distance is F. What will be the force between them when the distance between them is d/2?

• A. 4 F✓
• B. 2 F
• C. F
• D. F/2

Explanation: According to Coulomb's law of electrostatic force, the force between the two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. F = k q1q2/d² Where k is constant, q1 and q2 are two point charges and d the distance between them. If the distance between the charges is d/2 and there is no change in charges The new force becomes F’=kq1q2/(d/2)² F’=k q1q2/(d²/4) F’=4F Which means, force will be 4 times of the initial value.

Q157. What is the relationship between power, urrent and voltage?

• A. P=V/I
• B. P=VI✓
• C. 2P=l+V
• D. All of them

Explanation: is correct as it tells us about the actual relationship between power , current and voltage . Electric power is the rate at which work is done or energy is transformed into an electrical circuit. P=W/t P= QV/t *I = Q/t P= IV

Q158. Object A has a charge of 15 mC, and object B has a charge of 10 mC. Which statement is true about the electric forces on the objects?

• A. FAB = -3 FBA
• B. FAB = - FBA✓
• C. 3 FAB = - FBA
• D. -3 FAB = 2 FBA

Explanation: .

Q159. Magnetic force on a charged particle is:

• A. QvBl
• B. None of these
• C. QvB cosθ
• D. QvB sinθ✓

Explanation: When a charge moves through a magnetic field, a force is applied on it which is given by:F = QvB sinθQvBl is the motional EMF produced when a conductor moves through a static magnetic field.

Q160. In a full-wave rectification, the number of diodes used are:

• A. 1
• B. 2
• C. 3
• D. 4✓

Explanation: The full-wave rectifier circuit consists of 4 diodes arranged in a tetrahedral connection. When we have the upper side of the AC supply as positive, the current flows through D1 to the load and returns through D2 at the temporary negative terminal of the AC supply. When the bottom side of the AC supply is positive, due to the constant change in polarity, the current, conventionally, flows through D3 to the load and returns to the supply by passing through D4. It reaches the supply at the now negative terminal of the AC supply which is the upper side of the supply.

Q161. An alternation voltage V (in volts) is represented by the equation:V = 300 sin (100πt) What is the value of “f” for this voltage?

• A. 100 Hz
• B. 50 Hz✓
• C. 25 H
• D. 200 Hz

Explanation: Voltage = Maximum Voltage x sin (2πft)Therefore, 2f = 100 and frequency = 50 Hz

Q162. The use of a capacitor filter in a rectifier circuit gives satisfactory performance only when the load:

• A. The current is high
• B. The current is low✓
• C. Voltage is high
• D. The voltage is low

Explanation: A capacitor filter in a rectifier circuit is used to smooth out the output voltage and reduce the ripple factor.Only when load resistance is large, discharge time is large, and the current passing through it is low

Q163. Which one of the following is not electromagnetic in nature.

• A. X-rays
• B. Gamma rays
• C. Cathode rays✓
• D. Infrared rays

Explanation: Cathode ray is made up of electrons, so it is not an electromagnetic wave. They are deflected neither by the electric field nor by the magnetic field.

Q164. The waves which can travel directly along surface of the earth are known as

• A. ground waves✓
• B. X-ray
• C. α − rays
• D. sky waves

Explanation: The waves which can travel directly along surface of the earth are known as ground waves. The ground wave is the preferred propagation type for long distance communication using frequencies below 3 MHz (the earth behaves as a conductor for all frequencies below 5 MHz). The ground wave is also used for short distance communications using frequencies between 3 and 30 MHz.

Q165. A TV tower has a height of 100m. The average population density around the tower is 1000 per km2 . The radius of the earth is 6.4x106 m. × The population covered by the tower is

• A. 2x106
• B. 3x106
• C. 4x106✓
• D. 6x106

Explanation: This is the following solution:

Q166. The valence band and conduction band of a solid overlap at low temperature, the solid may be:

• A. a metal✓
• B. a semiconductor
• C. an insulator
• D. none of these

Explanation: According to band theory of solids, in the valence band and the conduction band overlap in conductors.

Q167. Assertion: In n-type semiconductor electrons are the majority charge carriers and holes are minority charge carriers.Reason: n-type semiconductor is electrically neutral.

• A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion.
• B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion.✓
• C. If Assertion is true statement but Reason is false.
• D. If both Assertion and Reason are false statements.

Explanation: In n-type semiconductor electrons are the majority charge carriers and holes are minority charge carriers and n-type semiconductor is electrically neutral.

Q168. Platinum wire becomes yellow at a temperature of _ degree C.

• A. 900
• B. 500
• C. 1300✓
• D. 1600

Explanation: If black wire of platinum is heated its colour first appears red, then yellow and finally white. This can be explained by wein’s displacement law. At low temperatures (500 degree celsius) the wire emits electromagnetic radiations of longer wavelengths so it appears dull red. As the temperature increases the wavelength emitted shortens and the colour changes from red to orange (1100 degree celsius) to yellow (1300 degree celsius) and ultimately white(1600 degree celsius) when radiations of all wavelengths are being emitted. PMC PAPER 23 2021 150-210

Q169. The electron is purely a _ when free.

• A. Particle nature
• B. Wave nature
• C. Dual nature✓
• D. It transforms to photon

Explanation: the electron is purely a dual nature when it's free. In quantum mechanics, electrons can behave as both particles and waves, depending on how they are observed or measured. This duality is known as wave-particle duality and is a fundamental aspect of quantum mechanics. When electrons are free, meaning they are not bound within an atom or molecule, their wave-like properties become more apparent.

Q170. Work function was given by:

• A. Newton
• B. Heisenberg
• C. Einstein✓
• D. Bohr

Explanation: Work function is the minimum energy required to cause the photoelectric effect. It is constant for a particular material. Absorption of energy equal to the work function causes electrons to be excited enough to come up to the surface of the material. Surplus energy will cause the emission of the electron from the surface. This can be explained from the Photoelectric Effect equation discovered by Einstein: KEmax = hfo + hf (where KEmax is the energy of the incident photon, hfo is the work function, hf is the KE of the electron)

Q171. In Davisson-Germer experiment, the diffracted electron beam from crystal shows

• A. Particle property
• B. Light property
• C. Wave property✓
• D. Quantum property

Explanation: Diffracted electron beam from crystal shows wave nature. Davisson Germer experiment showed that electron beams can undergo diffraction when passed through atomic crystals. This shows the wave nature of electrons as waves can exhibit interference and diffraction.

Q172. A set of Atoms in an excited state decays:

• A. In any general state with lower energy✓
• B. In any state when excited by electric field
• C. In any state when excited by magnetic field
• D. None of these options are correct

Explanation: As we know, atoms are stable in the ground state, when they move to another level by gaining energy, they get excited and are ready to lose energy to get back to the ground state. This shows, generally excited state atoms decay to any of the states with lower energy. Hence,the correct option is A in any general state with lower energy which is more stable than the excited state.

Q173. What is the number of spectral series in the hydrogen spectrum?

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

Explanation: The five spectral series are Lyman, Balmer, Paschen, Brackett and Pfund. In the Lyman series, the electron falls back to n = 1. The spectral lines obtained are in the UV region of the electromagnetic spectrum. In the Balmer series, the electron falls back to n = 2 and the spectral lines obtained are in the visible region of the EM spectrum. Paschen, Brackett, and Pfund spectral lines are obtained in the Infrared region of the EM spectrum.

Q174. How much energy is required to raise the temperature of 5.00 kg of lead from 20.0•c to its melting point of 327°C? The specific heat of lead is 128 J/kg ?•c.

• A. 1.96 x 10^5 J✓
• B. 4.04 X 10^5 J
• C. 1.07 X 10^5 J
• D. 8.15 x 10^4 J

Explanation: According to formula of Specific Heat Capacity ( c ), c = Q / m T Rearranging for Heat Energy ( Q ), Q = c m T Q = 128 x 5 x ( 327-20 ) Q = 1.96 x 105 J

Q175. The phase angle between two points is 3 pi. The distance between these points is 15 cm. What is the wavelength of the wave?

• A. 30 cm
• B. 45 cm
• C. 5 cm
• D. 10 cm✓

Explanation: According to the formula of Phase Difference = 2 / where, = phase difference ( phase angle between two points ) = wavelength of wave = path difference ( distance between two points on wave ) So, = 2 / 3 = 2 / 15 3 = 2 15 = 30 / 3 = 10 cm

Q176. A circular loop of area 0.05 m2 rotates in a uniform magnetic field of 0.2 T. If the loop rotates about its diameter which is perpendicular to the magnetic field, find the flux linked with the loop when its plane is normal to the field.

• A. 0.01 Wb✓
• B. 0 Wb
• C. 8.66 x 10-3 Wb
• D. 0.86 Wb

Explanation: Since the plane is normal (90), the area vector will be ( 90 - 90 ) = 0 with the field. B (magnetic field) = 0.2 T A (area) = 0.05 cm2 = 0 According to formula Flux will be = B A cos = 0.2 0.05 cos (0) Note cos (0) = 1 = 0.01 Wb

Q177. The shortest distance between two points on a travelling wave that have a phase difference of (pi/3) is 5 cm. If the wave has frequency 500 Hz, what is the speed of the wave?

• A. 300 m/s
• B. 150 m/s✓
• C. 300 cm/s
• D. 150 cm/s

Explanation: For wavelength, According to the formula of Phase Difference = 2 / where, = phase difference ( phase angle between two points ) = wavelength of wave = path difference ( distance between two points on wave ) So, = 2 / / 3 = 2 / 5 / 3 = 2 5 = 10 3 = 30 cm For speed of wave, v = f where, v = speed of wave f = frequency = wavelength of wave So, v = f v = 500 30 v = 15000 cm/s NOTE we convert cm/s m/s ( dividing by 100) 15000 cm/s 150 m/s

Q178. The force between two charges Q and q, separated by a distance d is F. What will be the force between them when distance between them is d/2?

• A. 4F✓
• B. 2F
• C. F
• D. F/2

Explanation: The force between two charges Q and q separated by distance d is given by Coulomb's law as:F = (1/4πε₀) * (Q*q/d²) where ε₀ is the electric constant. If the distance between the charges is reduced to d/2, the force between them will increase. The new force can be calculated as follows: F' = (1/4πε₀) * (Q*q/(d/2)²) F' = 4 * F So, the force between the charges will be four times greater when the distance between them is reduced to half. Mathematically other options are incorrect

Q179. The first law of thermodynamics can be stated as _.

• A. Q = ΔU +W✓
• B. Q + ΔU = W
• C. Q = ΔU - W
• D. Q = ΔU x W

Explanation: The first law of thermodynamics can be stated as: Q = ΔU + W where Q represents the heat added to the system, ΔU represents the change in internal energy of the system, and W represents the work done by the system.

Q180. A body of mass 10 kg is moved parallel to the ground, through a distance of 2 m. The work done against gravitational force is _.

• A. Zero✓
• B. 196 J
• C. -196 J
• D. 48 J

Explanation: Option A is correct since gravitational force only works perpendicular to the ground, so no work is done against gravitational force. Options B, C, and D are incorrect since no work can be done against gravitational force.

Q181. A stationary wave is set up on a string that is fixed at both ends. The frequency of the wave is 400 Hz. If the speed of the wave is 480 m/s, then what is the length of the string?

• A. 1.2m
• B. 0.84m
• C. 0.60m✓
• D. 0.42m

Explanation: Option A is correct since by applying the formula: F = v / 2L 2L = v / F , 2L = 480 / 400 = 1.2 / 2 = 0.60 m Options B, C, and D are incorrect since the given options are wrong answers.

Q182. The centripetal force is zero when the centrifugal force is _.

• A. Equal
• B. Zero✓
• C. Maximum
• D. None of these options are correct

Explanation: Option B is correct since centripetal force and centrifugal force are equal in magnitude and opposite in direction, so it will also be zero.

Q183. Calculate the charge passing through the circuit if it's current is 10 Ampere and the recorded time is 15 seconds:

• A. 1,500 Coulombs
• B. 150 Coulombs✓
• C. 13,400 Coulombs
• D. 140 Coulombs

Explanation: Option B is correct since after applying the charge formula which is, Q = ITQ = 10 x 15 = 150 Columbs. As it is numerical only one option is correct.

Q184. Heat is the energy that flows across the?

• A. Surroundings
• B. Boundaries of the system✓
• C. Only within the system
• D. All of these

Explanation: In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. The other options are incorrect

Q185. A constant force of 10N is applied in horizontal direction and distance travelled in the direction of force is 2m,then work done is _.

• A. 50J
• B. 20J✓
• C. 22J
• D. 10J

Explanation: The work done is calculated using the formula: Work = Force x Distance x Cosine(angle)As the force is applied in the horizontal direction, the angle between the force and the displacement is 0 degrees, and cosine(0) = 1. Therefore, we can simplify the formula to:Work = Force x DistanceSubstituting the given values, we get:Work = 10 N x 2 m = 20 Joules (J)Therefore, the work done is 20 J. Mathematically the other options are incorrect

Q186. A strong magnetic field is applied on a stationary electron, then the electron _.

• A. Moves in the direction of the field.
• B. Moves perpendicular to the direction of the field.
• C. Moves opposite to the direction of the field.
• D. Remains stationary✓

Explanation: A strong magnetic field is applied on a stationary electron. Then the electron remains stationary because magnetic force act on moving charge. Hence, the option C is the correct answer.

Q187. If number of loops are increased than according to Faraday law _ will increase.

• A. Voltage✓
• B. Electric field
• C. Magnetic field
• D. All of these

Explanation: According to Faraday's law, an increase in the number of loops will result in an increase in the induced EMF or voltage. However, this does not necessarily mean that the electric and magnetic fields will also increase. The induced EMF depends on the rate of change of magnetic flux through the loop, which is related to the magnetic field. So, an increase in the number of loops may increase the magnetic field, but it may not have a direct effect on the electric field. Therefore only voltage will increase The rest are incorrect

Q188. A wire of uniform area of cross-section A and length L is cut into two equal parts, the resistivity of each part _.

• A. Doubles
• B. Halves
• C. Remains the same✓
• D. Increases three times

Explanation: The resistivity is actually dependent on the material. If the length and/or the cross-sectional area change, it does not affect the resistivity. Therefore, the resistivity of the material remains the same. The other options are incorrect

Q189. In case of harmonic oscillator total energy remains _.

• A. Variable
• B. Infinity
• C. Constant✓
• D. Zero

Explanation: The total energy of the system remains constant throughout the motion, and mechanical energy is conserved in simple harmonic motion. This means that the sum of kinetic and potential energies at any point is always equal to the total energy of the system.

Q190. A variable force F = x is applied what will be the work done in moving the particle from X= 0 to 1

• A. 2 J
• B. 1 J
• C. 0.5 J✓
• D. 5 J

Explanation: The work done in moving a particle from x=0 to x=1 when a variable force F=x is applied can be found by integrating the force over the distance. The work done W is given by: W = ∫x=0 to x=1 F(x) dx W = ∫x=0 to x=1 x dx W =[x^2/2] from 0 to 1 W = (1^2/2) - (0^2/2) W = 1/2 units of work Therefore, the work done in moving the particle from x=0 to x=1 with a variable force F=x is 1/2 units of work. Mathematically the options are incorrect

Q191. Complete the sequence: 2, 15, 41, 80, _

• A. 111
• B. 120
• C. 121
• D. 132✓

Explanation: Multiples of 13 are being added + 13 +26 +39 so now you'll add 52

Q192. 8, 10, 14, 18, _ , 34, 50 , 66:

• A. 24
• B. 25
• C. 26✓
• D. 27

Explanation: The increasing order is +2,+4, +4, +8, +16, +16 8 + 2= 10 10 + 4= 14 14 + 4 = 8 18 + 8= 26

Q193. Blueberries cost more than strawberries.Blueberries cost less than raspberries.Raspberries cost mre than strawberries and blueberries.If the first two statements are true, the third statement is:

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

Explanation: Explanation Because the first two statements are true, raspberries are the most expensive of the three.

Q194. The Emporium Mall has more stores than the Pakages Mall.The Amanah Mall has fewer stores than the Pakages Mall.The Emporium Mall has more stores than the Amanah Mall.If the first two statements are true, the third statement is

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

Explanation: Explanation From the first two statements, you know that the Emporium mall has the most stores, so the Emporium Mall would have more stores than the packages Mall.

Q195. I. Car manufacturing companies have recently increased the prices of mid-sized cars. II.The Government recently increased the duty on mid-sized cars.

• 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 the statements I and II are independent
• D. Both the statements I and 11 are effects of so

Explanation: Is correct as the government increased the duty on mid sized cars which is the cause due to which the companies have increased the prices of mid sized cars which is the effect

Q196. An autograph can not exist without?

• A. Actor
• B. Singer
• C. Player
• D. Pen✓

Explanation: An autograph is defined as a person's handwritten signature, mostly of someone famous among the masses. As a pen is necessary to do a signature by hand, hence it is the answer.