Balochistan Mdcat Mock Paper 1 — Solved Past Paper with Answers

Q1. 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.

Q2. Select the option which fits appropriately in the blank: The robber broke into the house and _ (tie) the lone occupant with ropes.

• A. Tied✓
• B. Ties
• C. Tie
• D. Tying

Explanation: 'Broke' implies past tense so the past tense of tie is 'tied'.

Q3. Select the option which fits appropriately in the blank: The dog sprang _ him.

• A. On
• B. Upon✓
• C. In
• D. Over

Explanation: 'Upon' is a preposition. up and on; upward so as to get or be on: He climbed upon his horse and rode off. It means the same as on/onto as is usually interchangeable.

Q4. Find an error in the following sentence: Everyone who was injured in the accident were taken to the hospital.

• A. Everyone who was injured
• B. In the accident
• C. Were taken✓
• D. To the hospital

Explanation: 'Everyone' is a singular term, so 'was' will be used with it.

Q5. Select the option which fits appropriately in the blank: Everyone _ done his or her homework.

• A. Has✓
• B. Have
• C. Had
• D. Non

Explanation: The indefinite pronouns anyone, everyone, someone, no one, nobody are always singular and, therefore, require 'singular verbs'. Everyone has done his or her homework.

Q6. Select the option which fits appropriately in the blank: _ icon like this is called _ hourglass.

• A. An..a
• B. An...the
• C. An..an✓
• D. The..an

Explanation: The reason why we have 'an hourglass', instead of 'a hourglass', is because we tend to focus on the sounds. Since 'h' is silent, hour is pronounced as 'our', with the sound of 'o' in the start. When a word begins with a vowel sound, we add 'an' before the word.

Q7. Find an error in the following sentence: If I had been thirsty, I would have drank the lemonade without waiting for you.

• A. If I had been thirsty
• B. I would have
• C. Drank the lemonade✓
• D. Without waiting for you.
• E. There is nothing wrong in the sentence

Explanation: Option A : As explained above this answer is incorrect.Option B : As explained above this answer is incorrect.Option C: "Drunk" is the past participle of "drink". The phrase "drunk the lemonade" would be the correct alternative to C.Option D : As explained above this answer is incorrect.Option E : As explained above this answer is incorrect.

Q8. The process of determining the locus for particular biological traits includes?

• A. Replication
• B. Recombination
• C. Gene mapping✓
• D. None of these options is correct

Explanation: Option A: Replication refers to the process of copying DNA during cell division and is not directly related to gene mapping.Option B: Recombination is the process by which genetic material is exchanged between chromosomes during meiosis, and can be used to map genes to particular regions of a chromosome. However, it is not the sole process involved in gene mapping.Option C: Gene mapping describes the methods used to identify the locus of a gene and the distances between genes. Gene mapping can also describe the distances between different sites within a gene. The essence of all genome mapping is to place a collection of molecular markers onto their respective positions on the genome. Option D: As explained above this option is incorrect.

Q9. The attraction between water molecules and the cell wall of xylem is termed as:

• A. Cohesion
• B. Tension
• C. Adhesion✓
• D. Imbibition

Explanation: Option A: Cohesion refers to the attraction between water molecules themselves, which allows them to stick together and form a continuous column in the xylem. Option B: Tension refers to the force that pulls water up through the xylem, which is caused by transpiration at the leaves. Option C: Adhesion is a molecular attraction between "unlike" molecules. In the case of the xylem, adhesion occurs between water molecules and the molecules of the xylem cell walls. Cohesion is a molecular attraction between "like" molecules. In water, cohesion occurs due to hydrogen bonding between the water molecules.Option D: Imbibition refers to the process by which a solid absorbs water, such as a seed swelling when it takes up water.

Q10. Gametes in animals are produced by which of the following?

• A. Mitosis
• B. Meiosis✓
• C. Fission
• D. All of these

Explanation: Only meiosis is the type of cell division that will produce haploid number of chromosomes (n). Gametes contain haploid (n) number of chromosomes. Mitosis produces diploid chromosomes and fission does not occur in animals.

Q11. A neural pathway that controls an action reflex is called:

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

Explanation: Option A: A nerve cell is a basic unit of the nervous system that transmits signals throughout the body.Option B: A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain but synapse in the spinal cord. This allows for faster reflex actions to occur by activating the spinal motor neurons without the delay of routing signals through the brain.Option C: Receptor cells are specialized cells that respond to specific stimuli such as light, sound, or chemicals. Option D: A mixed nerve is a nerve that contains both sensory and motor fibres.

Q12. Who discovered the bacteria causing tuberculosis and also developed various techniques of media preparation and maintenance of pure culture?

• A. Robert Koch✓
• B. Louis Pasteur
• C. Alexander Fleming
• D. Antonie van Leeuwenhoek

Explanation: Fact.

Q13. Aslam and his friends were making too much noise. Their father got really _ at them.

• A. Afraid
• B. Angry✓
• C. Kind
• D. Strong

Explanation: Angry is used for feeling of showing strong annoyance.Since noise is unwanted, the father would get angry by it, instead of kind, strong or afraid.

Q14. _ anyone _ a pencil I could borrow?

• A. Do ... have
• B. Does.. have✓
• C. Do .. has
• D. Does.. has

Explanation: Do is used for plural subject and does is used for singluar subject and anyone shows singular subject.so, first blank is does. For 1st person and 2nd person we use have to show possession and for 3rd person we use has to show possession. And 'I' is 1st person so , second blank refers have. Thus option A,C and D are incorrect

Q15. Choose the correct sentence.

• A. Does your tram leaw before eight o'clock?
• B. Does your train leave before eight clock?
• C. Does your train leave before eight o'clock?✓
• D. Do your train leave before eight o'clock?

Explanation: In this corrected sentence: "Does" is the correct auxiliary verb used with a singular subject to form a question in the present tense. "your" is the possessive pronoun, indicating that the train belongs to the person being addressed. "train" is the noun representing the mode of transportation. "leave" is the main verb, representing the action of the train departing or starting its journey. "before eight o'clock" is a prepositional phrase indicating the time when the action (leaving) is happening. With the "Does" correction, the sentence now asks whether the person's train departs or starts its journey before 8 o'clock. It is grammatically correct and properly formed.

Q16. I found this bangle while digging in the backyard. I don't know who it belonged to.

• A. I found this bangle
• B. While digging
• C. In the backyard
• D. I don't know who it belonged to.✓

Explanation: As the person is speaking in present tense, all verbs should be in present tense, hence it should be "I don't know whom it belongs to.

Q17. I lived on _ Main Street when I first came to town.

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

Explanation: In general, no article is used with proper nouns, mass nouns where the reference is indefinite, or plural count nouns where the reference is indefinite.

Q18. Which of the following blood vessels have the highest pressure of blood?

• A. Aorta✓
• B. Pulmonary arteries
• C. Pulmonary veins
• D. Vena cava

Explanation: As shown in the figure, the aorta and arteries have the highest pressure. The mean aortic pressure (solid red line) is about 90 mmHg in a resting individual with normal arterial pressures. The mean blood pressure does not fall very much as the blood flows down the aorta and through large distributing arteries.

Q19. Autoimmune diseases act as the principle of:

• A. Self against antigens
• B. Antigen against self
• C. Self against self✓
• D. Antigen self destroyed

Explanation: Autoimmune disease occurs when a specific adaptive immune response is mounted against self antigens(hence self mounts against self). The normal consequence of an adaptive immune response against a foreign antigen is the clearance of the antigen from the body.

Q20. In human heart, the left atrium receives:

• A. The superior vena cava
• B. The inferior vena cava
• C. The coronary sinus
• D. The four pulmonary veins✓

Explanation: The Right Atrium receives deoxygenated blood from the Superior Vena Cava, Inferior Vena Cava and the Left Atrium receives blood from four pulmonary veins. As shown in the diagram below:

Q21. Antibodies are manufactured in:

• A. T Lymphocytes
• B. Red Blood Cells
• C. Platelets
• D. B Lymphocytes✓

Explanation: Antibodies are produced by specialized white blood cells called B lymphocytes (or B cells). B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors of the precursor B cell. Once released into the blood and lymph, these antibody molecules bind to the target antigen (foreign substance) and initiate its neutralization or destruction. T lymphocytes are part of the immune system and develop from stem cells in the bone marrow. They help protect the body from infection and may help fight cancer by attacking foreign particles. Platelets, or thrombocytes, are small, colorless cell fragments in our blood that form clots and stop or prevent bleeding. Red Blood Cells contain the red pigment hemoglobin which transports Oxygen

Q22. When the temperature of the surrounding environment rises, body responds by:

• A. Vasoconstriction
• B. Vasodilation✓
• C. Shivering
• D. Raising body hairs

Explanation: If the surrounding temp is higher than normal then the body will want to lose heat and hence Vasodilation will occur so that more blood passes near the surface of the body allowing rapid exchange of heat allowing the body to cool.Vasodilation occurs due to Homeostasis which is the ability to maintain a stable internal environment despite changes in the external environment. The other scenario that is possible is that if the temperature of the environment decreases, then the body will want to conserve heat, so Vasoconstriction will occur preventing heat exchange at the surface of the body.The muscles will undergo involuntary contractions (shivering) so that the movements of the muscles causes heat to be produced. Piloerection will occur where muscles will contract at the base of each body hair making them stand on end trapping an insulating air layer.

Q23. Which one is not an energy releasing process?

• A. Glycolysis
• B. Photosynthesis✓
• C. Respiration
• D. Krebs cycle

Explanation: In photosynthesis, energy is not released because when carbon dioxide and water react, they form oxygen and glucose so photosynthesis is the process in which it produces food for the plant and uses sunlight as its energy source and, no energy is produced.

Q24. The function of lymph node is to filter:

• A. Blood
• B. Lymph✓
• C. Semen
• D. Amniotic fluid

Explanation: Option B is correct since the lymph capillaries, containing lymph fluid, pass through the lymph nodes as they return the lymph into the blood circulation.

Q25. Inbreeding increases the frequency of which of the following?

• A. Heterozygous
• B. Genetic diversity
• C. Genetic linkage
• D. Homozygous✓

Explanation: Correct option: D (Inbreeding increases the frequency of homozygous phenotypes)

Q26. Which of the following structure provides greater pathogenicity to the bacteria?

• A. Slime✓
• B. Cell wall
• C. Cell membrane
• D. Capsule

Explanation: The slime layer of bacteria can play a role in pathogenicity by helping bacteria to adhere to surfaces, evade the immune system, and resist antibiotics.

Q27. Which of the following is heterozygote?

• A. RR
• B. rr
• C. Both A and B
• D. None of them✓

Explanation: Correct option: D (None of the options are heterozygous phenotype).A heterozygote refers to an individual or organism that carries two different alleles for a specific gene

Q28. What are the total number of amino acids found in a haemoglobin molecule?

• A. 575
• B. 576
• C. 574✓
• D. 573

Explanation: Correct option: C (fact) (There are 574 amino acids in a haemoglobin molecule).A haemoglobin molecule consists of a total of 574 amino acids. It is made up of four protein chains: two alpha chains and two beta chains. Each alpha chain consists of 141 amino acids, and each beta chain consists of 146 amino acids. Therefore, the total number of amino acids in a haemoglobin molecule is 2 * 141 (alpha chains) + 2 * 146 (beta chains) = 282 + 292 = 574. Hence, option C is the correct answer.

Q29. Nervous system of nematodes consists of which of the following?

• A. Ventral nerve cord
• B. Dorsal nerve cord
• C. Lateral nerve cord
• D. All of these✓

Explanation: d) All of these, Explanation: The correct answer is d) All of these. Nematodes' nervous system consists of a ventral nerve cord, lateral nerve cords, and other interconnected nerve structures that allow them to sense their environment, coordinate movements, and carry out various essential functions.

Q30. Skin colour in man is controlled by how many pairs of genes?

• A. 1
• B. 2
• C. 3✓
• D. None of these

Explanation: Correct option: C(Fact) (3 pairs of genes control skin colour in man).

Q31. A non-protein chemical compound which is required for protein's biological activity is:

• A. Coenzyme
• B. Cofactor✓
• C. DNA
• D. RNA

Explanation: Cofactor is a non-protein chemical compound required for a proteins biological activity.

Q32. Where is the double stranded DNA of the bacteriophage found?

• A. Tail
• B. Sheath
• C. Collar
• D. Head✓

Explanation: Correct option :D This option is correct because the double stranded DNA of bacteriophage is found in the head.

Q33. Under the microscope, the bacteria appear a bluish-purple colour. Which class of bacteria are on the slide?

• A. Gram-positive✓
• B. Gram-negative
• C. Both A and B
• D. None of these

Explanation: Correct option: A (fact) (Gram positive bacteria retain bluish purple dye when being tested). If the bacteria appear bluish-purple under the microscope, it indicates that they have retained the crystal violet stain after the Gram staining procedure. Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which allows them to retain the crystal violet stain and appear purple. Gram-negative bacteria, on the other hand, have a thinner peptidoglycan layer and are counterstained with a red or pink color. Therefore, the bacteria on the slide are most likely Gram-positive.

Q34. The book name in which Darwin published the theory of evolution is?

• A. The origin of species by natural selection
• B. The origin of species✓
• C. The evolution of species
• D. The evolution of species by means of natural selection

Explanation: Correct option: B (fact) (Darwin published the theory of evolution in his book The Origin Of Species)

Q35. The nervous system of arthropods has:

• A. A brain, a ventral nerve cord and several ganglia✓
• B. A brain, a dorsal nerve cord and several ganglia
• C. A brain, a dorsal and ventral nerve cord and several ganglia
• D. A ventral nerve cord and several ganglia

Explanation: A highly deyeloped nervous system is present. It consists of paired ganglia (simple brain) connected to a ventral double nerve cord. A ganglion is present in each segment. Nerves arise from these ganglia. The sensory organs are usually a pair of compound eyes and antennae etc.

Q36. Which of the following is the best desciption of bacteriophage?

• A. Fungus
• B. Prokaryote
• C. Living organism
• D. Obligate intracellular parasite✓

Explanation: Bacteriophages are actually obligate intracellular viruses. This means that they can only replicate and complete their life cycle by infecting and taking over the machinery of host bacterial cells. So, option D is correct.

Q37. What type of viruses are the polioviruses?

• A. DNA enveloped virus
• B. RNA enveloped virus
• C. DNA naked virus
• D. RNA naked virus✓

Explanation: Correct option is D. RNA naked virus is a virus that has an RNA genome but no envelope. The RNA genome is directly exposed to the environment. RNA naked viruses are more common than DNA naked viruses. Some examples of RNA naked viruses include the poliovirus and the rhinovirus.

Q38. Mating with non-relatives is known as?

• A. Inbreeding
• B. Outbreeding✓
• C. Breeding
• D. None of these

Explanation: Mating is the process in which animals interact by sexual intercourse. When they do not breed within their relatives, we call it outbreeding, therefore option B is correct.

Q39. Which scientist came up with the term "cell"?

• A. Schwann
• B. Scheilden
• C. Robert Hooke✓
• D. Both Options A and B are correct

Explanation: The cell was discovered by Robert Hooke in 1665, in a Cork piece, in which he saw small compartments. He named them "cells" because they resembled small rooms "cellulae" (Latin) in which Monks used to live. Scheilden and Schwann coined the cell theory AFTER the cell had been discovered and named.

Q40. Two species can avoid competition and can make better use of the environment's resources by occupying different:

• A. Adaptation
• B. Polymorphism
• C. Niches✓
• D. Specialization

Explanation: A niche is an exact position or location, so if two species occupy different niches, they will be having separate reservoirs of environmental resources. Hence, there will be no competition to survive and avail the resources. However, if they occupy different polymorphisms, adaptations, or specializations (options A, C, and D) they will still be sharing the resources which will create competition.

Q41. Who discovered the bacteria causing Tuberculosis and also developed various techniques of media preparation and maintenance of pure culture?

• A. Robert Koch✓
• B. Louis Pasteur
• C. Alexander Fleming
• D. Leeuwenhoek

Explanation: Robert Koch was a German scientist who discovered the causative agents for deadly diseases like tuberculosis, cholera, and anthrax. He discovered solid culture media and was the first to obtain a pure culture of bacteria.

Q42. What percentage of glucose is normally found in human blood?

• A. 0.008
• B. 0.0008
• C. 0.018
• D. 0.08✓

Explanation: Our blood normally contains 0.08% glucose.

Q43. The substrate binds to a specific region on the enzyme called?

• A. Key
• B. Active site✓
• C. Hyperactive site
• D. None of these options are correct

Explanation: The substrate binds to a specific region on the enzyme called the active site. The active site is a pocket or crevice on the surface of the enzyme that is complementary to the shape of the substrate. The substrate binds to the active site through a series of weak interactions, such as hydrogen bonds and van der Waals forces. Once the substrate is bound to the active site, the enzyme can catalyze the reaction.

Q44. Which of the following impart a red colour to rose petaIs?

• A. Chloroplast
• B. Chlorophyll
• C. Chromoplast✓
• D. Leucoplast

Explanation: Chromoplast are pigments containing colored plastids that impart characteristic colors to different parts of the plant.

Q45. What enzyme is found in the thylakoid membrane that facilitates chemiosmosis?

• A. ATP ligase
• B. ATP kinase
• C. ATP synthase✓
• D. ATP dehydrogenase

Explanation: ATP synthase is the enzyme that makes ATP by chemiosmosis. It allows protons to pass through the membrane and uses the free energy difference to phosphorylate adenosine diphosphate (ADP), making ATP.OPTION A: The ATP-dependent DNA ligases catalyze the joining of single-stranded breaks (nicks) in the phosphodiester backbone of double-stranded DNA in a three-step mechanism.OPTION B: Protein kinases catalyse the transfer of the gamma phosphate from nucleotide triphosphates (often ATP) to one or more amino acid residues in a protein substrate side chain, resulting in a conformational change affecting protein function.OPTION C: ATP synthase is a protein that catalyzes the formation of the energy storage molecule ATP using ADP and inorganic phosphate.OPTION D: Dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor.

Q46. _ are biologically active proteins.

• A. Glycoproteins
• B. Enzymes✓
• C. Activators
• D. Inhibitors

Explanation: Biologically active refers to the substance having an effect on a living organism, tissue, or cell. Enzymes are biologically active proteins. Enzymes are specialized proteins that act as catalysts in biochemical reactions, speeding up the conversion of substrates into products. They play a crucial role in various biological processes by facilitating chemical reactions necessary for metabolism, growth, and other cellular functions. The other options, glycoproteins, activators, and inhibitors, may also be proteins, but they are not specifically defined as biologically active proteins like enzymes.

Q47. How many ml of oxygen are present in a litre of water?

• A. 10✓
• B. 20
• C. 40
• D. 200

Explanation: Water has a low oxygen content compared to equal volume of air. A litre of water contains less than "10 ml" of oxygen.

Q48. A pure breeding tall pea plant was crossed to a dwarf plant, what will be the frequency of dwarf plants in F1?

• A. 0.25
• B. 0.5
• C. 0✓
• D. 1

Explanation: Here is the cross, P1 generation: True breeding tall (TT) ✕ true breeding small (tt) F1 generation:All the offsprings are heterozygous tall i.e no dwarf plant is observed in the F1 generation.

Q49. In this stage of photosynthesis, ATP and NADPH are converted to ADP+Pi and NADP+

• A. Light dependent reaction
• B. Light independent reaction✓
• C. Both of these options are correct
• D. None of the above options are correct

Explanation: The Calvin cycle takes place in the stroma and uses the ATP and NADPH from the light-dependent reactions to fix carbon dioxide, producing three-carbon sugars—glyceraldehyde-3-phosphate, or G3P, molecules. The Calvin cycle converts ATP to ADP and Pi, and it converts NADPH to NADP+ in light-independent reactions.

Q50. Sex pili are formed in which of the following processes?

• A. Sexual reproduction
• B. Binary fission
• C. Mitosis
• D. Conjugation✓

Explanation: Conjugative or sex pili are special projections originating from many bacteria's cytoplasmic membranes. They are involved in the exchange of genetic material between the bacteria. This method is known as conjugation. It is analogous to sexual reproduction, hence also called 'sex' pili.

Q51. Which of the following combination is an example of self-replicating organelles?

• A. Mitochondria and Ribosomes
• B. Mitochondria and Chloroplast✓
• C. Mitochondria and Vacuole
• D. Mitochondria and lysosomes

Explanation: Both mitochondria and chloroplasts are self replicating as they contain their own DNA and enzymes.

Q52. The G3P is end product of which process?

• A. Kreb's cycle
• B. Calvin cycle✓
• C. Chemiosmosis
• D. Electron transport chain (ETC)

Explanation: The Calvin cycle forms glyceraldehyde - 3 - phosphate (G3P) from inorganic carbon dioxide.

Q53. In females, the progesterone and estrogen hormones are secreted by?

• A. Ovaries✓
• B. Testes
• C. Egg
• D. Kidneys

Explanation: The correct answer is ovaries. The ovaries are the female reproductive organs that produce eggs and secrete the hormones estrogen and progesterone. Estrogen is responsible for the development of female sex characteristics, such as breasts and hips. Progesterone is responsible for preparing the uterus for pregnancy.

Q54. Inbreeding reduces the fitness of a population. This is the result of which increased genetic affect of inbreeding?

• A. Rate of spontaneous mutation
• B. Levels of aggression
• C. Genetic diversity
• D. Expression of deleterious recessive traits✓

Explanation: Inbreeding increases offspring homozygosity and usually results in reduced fitness. In homozygous genotypes, recessive deleterious alleles are unmasked and benefits of heterozygosity in overdominant loci are lost.

Q55. Cellular respiration is essentially what type of process?

• A. Oxidation
• B. Reduction
• C. Redox✓
• D. None of the above options is correct

Explanation: Cellular respiration is a redox reaction, i.e., both oxidation & reduction occurs. There is both loss and gain of electrons in respiration. Oxidation refers to electron loss, and reduction refers to electron gain. Here, glucose molecules are oxidized and oxygen molecules are reduced to generate water molecules.

Q56. The path taken by the nerve impulses in a reflex is called a:

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

Explanation: The reflex arc is the pathway of impulses in the reflex action. The spinal cord acts as the center of reflex action. It begins with a sensory neuron at a receptor (e.g., a pain receptor in the fingertip) and ends with a motor neuron at an effector (e.g., a skeletal muscle).

Q57. The neurons responsible for converting various external stimuli that come from the environment into corresponding internal stimuli is called:

• A. Motor
• B. Sensory✓
• C. Both A and B
• D. Mixed

Explanation: The neurons responsible for converting various external stimuli that come from the environment into corresponding internal stimuli are called sensory neurons.

Q58. 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!".

Q59. In mixed inhibition, the allosteric effect affects:

• A. Shape of substrate
• B. Shape of inhibitor
• C. Shape of enzyme✓
• D. None of these options are correct

Explanation: The allosteric effect in mixed inhibition, alters the shape of enzyme so no substrate can bind to an ultimately no activity can be carried out.

Q60. In cell fractionation, various components of cells including its organelles can be isolated in different layers depending upon:

• A. Their physical properties like size and weight
• B. Physical properties of the medium like its density
• C. Their electrical properties like their charges
• D. Both Options A and B are correct✓

Explanation: In cell fractionation, various components of a cell including its organelle can be isolated in different layers depending upon their physical properties like size, weight, density,

Q61. The communication between the two hemispheres is the function of:

• A. Corpus callosum✓
• B. Hindbrain
• C. Cerebellum
• D. Cerebrum

Explanation: The communication between the two hemispheres is the function of the corpus callosum. The corpus callosum is a large band of nerve fibers that connects the left and right hemispheres of the brain. It allows the two hemispheres to communicate with each other and to share information.

Q62. While bound to the active site, the substrate is converted into which of the following?

• A. Complex
• B. Substrate of high energy
• C. Product of reaction✓
• D. Both Options A and B are correct

Explanation: When a substrate has been bound to the active site, the enzyme cleaves its bonds and it is converted to product.

Q63. The number of autosomes in the human sperm is:

• A. 11
• B. 22✓
• C. 44
• D. 45

Explanation: A human sperm is a haploid gamete that contains half the number of chromosomes found in somatic cells. Thus, Somatic cells: have 46 chromosomes (44 autosomes + 2 sex chromosomes). Gametes: 23 chromosomes (22 autosomes + 1 sex chromosome). 45 chromosomes are found in diploid cells of Turner's Syndrome cases.

Q64. Hemophilia is a sex-linked recessive disease. A mother that is a carrier of the disease mates a healthy male. Which of the following statements is true?

• A. The daughters are just likely to be hemophilic as the sons are
• B. 50% of the daughters will have hemophilia
• C. None of the children will have hemophilia because the mother is the only carrier
• D. 50% of sons will have hemophilia✓

Explanation: In the given scenario where a mother is a carrier of the sex-linked recessive disease hemophilia and mates with a healthy man, the following statement is true: 50% of sons will have hemophilia. Hemophilia is an X-linked recessive disorder, which means the gene responsible for hemophilia is located on the X chromosome. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). When a carrier mother (X^hX) mates with a healthy man (XY), the possible outcomes for their offspring are as follows: Sons: There is a 50% chance that a son will inherit the X chromosome with the hemophilia allele (X^h) from the carrier mother, resulting in the son having hemophilia (X^hY). There is also a 50% chance that a son will inherit the healthy X chromosome from the mother (X) and the Y chromosome from the father (Y), resulting in the son being unaffected by hemophilia (XY). Daughters: There is a 50% chance that a daughter will inherit the X chromosome with the hemophilia allele (X^h) from the carrier mother and a healthy X chromosome from the father (X^hX). Therefore, the correct statement is that 50% of sons will have hemophilia.

Q65. Which of the following best describes the prosthetic group?

• A. Loosely bonded non-protein part of an enzyme
• B. Cofactor consists of metal ion
• C. Covalently bounded non-protein part of an enzyme✓
• D. None of these options are correct

Explanation: Covalently bounded non-protein part of the enzyme.A prosthetic group is a non-protein molecule that is covalently bound to an enzyme and is necessary for its proper function. Unlike a loosely bound non-protein part, a prosthetic group is tightly and permanently attached to the enzyme. It plays a crucial role in the enzyme's catalytic activity or structural stability.

Q66. What does ATP provide during photosynthesis?

• A. Mechanical energy
• B. Physical energy
• C. Chemical energy✓
• D. All of these

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

Q67. Some bacteria have resistant organelles called as:

• A. Spores✓
• B. Cysts
• C. Granules
• D. All of these options are correct

Explanation: Option A is correct since spores are considerably more resistant to moist and dry heat than non-sporulating bacteria. Spores are more resistant to unfavorable environmental conditions. Cysts are less resistant compared to spores.

Q68. What is an example of an oviparous mammal?

• A. Penguin✓
• B. Bat
• C. Whales
• D. Elephant

Explanation: Penguins are oviparous, which means they lay eggs. Penguins lay eggs and incubating them. After mating, the female penguin lays one or two eggs, depending on the species, and then both the male and female take turns incubating the eggs by sitting on them to keep them warm. Once the eggs hatch, the parents continue to care for the chicks until they are ready to survive on their own. Whales, Bats and Elephants all reproduce sexually.

Q69. Which of the following parts of cell is described as fluid mosaic?

• A. Chloroplast
• B. Vacuole
• C. Cell membrane✓
• D. Endoplasmic reticulum

Explanation: Cell membrane describes the structure of the fluid mosaic model, in which fluid is a lipid bilayer and proteins float like icebergs in the sea.

Q70. Which cells secrete pepsinogen?

• A. Mucous
• B. Parietal
• C. Zymogen✓
• D. Oxyntic

Explanation: Zymogen cells secrete pepsinogen.

Q71. Which of the following structure primarily helps in attachment of bacteria on various surfaces?

• A. Pilli✓
• B. Flagella
• C. Both A and B
• D. None of these

Explanation: Flagella help in locomotion whereas pilli help in attachment.

Q72. A chemical component that is NOT found in all viruses is _.

• A. Protein
• B. Lipids✓
• C. DNA
• D. RNA

Explanation: Lipid envelope is the chracteristic of only some viruses, who also gain it by their host cells after they cause it to burst. The only necessary features in all viruses are protien coat and nucleic acids.

Q73. The lighter, inner section of the brain is called:

• A. White matter✓
• B. Gray matter
• C. Reflex arc
• D. Medulla

Explanation: The lighter, inner section of the brain is called white matter. It is made up of nerve fibres that connect different parts of the brain. Gray matter on the other hand is the outer layer of the brain and spinal cord. It is made up of cell bodies, dendrites, and synapses.

Q74. Where the heterozygote is indistinguishable from one of the homozygotes the allele involved is said to be?

• A. Recessive
• B. Dominant✓
• C. Both A and B
• D. None of these

Explanation: In the dominant allele, in both homozygous and heterozygous form the genotype cannot be known as the phenotype in both is same.

Q75. What protein, present in sarcomeres, is responsible for the passive elasticity of muscle?

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

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

Q76. Which statement correctly describes the alimentary canal of hydra?

• A. The alimentary canal is formed from the endodermal cells
• B. The alimentary canal has a single opening
• C. The alimentary canal is saclike
• D. All of the above✓

Explanation: In simple invertebrates, such as hydras and flatworms, the digestive system is a sac with a single opening. A hydra has a central cavity that holds prey; the cavity is lined by a layer os specializd cells that secrete digestive enzymes to break down the prey's tissues.

Q77. During aristotle time, it was thought that

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

Explanation: During Aristotle's time it was believed that all living things were specially created by nature and that they were each designed to fulfill a specific purpose or function. This concept was known as teleology, which held that everything in nature had a predetermined end or goal The rest options are incorrect

Q78. Sperms are developed at what temperature?

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

Explanation: Explanation for this question will be added soon.

Q79. Unit of carbohydrate is ?

• A. Monosaccharides✓
• B. Amino acids
• C. Fatty acids
• D. All

Explanation: Monosaccharide: The most basic, fundamental unit of a carbohydrate. These are simple sugars with the general chemical structure of C6H12O6.

Q80. In the human body, the group formed by neurons enclosed in the membrane at certain body parts is called?

• A. Benign
• B. Malign
• C. Ganglion✓
• D. Neuroglia

Explanation: Ganglia is the plural of the word ganglion. Ganglia are clusters of nerve cell bodies found throughout the body. They are part of the peripheral nervous system and carry nerve signals to and from the central nervous system.

Q81. The rate of reaction is directly proportional to the concentration of an enzyme. Which statement is incorrect in this respect?

• A. If the concentration is doubled the rate will become two-fold.
• B. If the concentration is doubled the rate will become one-fold.✓
• C. This relation is for an unlimited time period with unlimited enzyme concentration.
• D. All of these options are correct.

Explanation: The rate of a chemical reaction is defined as the rate of change in concentration of a reactant or product divided by its coefficient from the balanced equation Doubling the concentration would not cause the rate to become one fold thus this option is correct as per the question

Q82. Sperms are produced in:

• A. Urethra
• B. Sperm dust
• C. Pancreas
• D. Testes✓

Explanation: Explanation for this question will be added soon.

Q83. Bacteriochlorophylls does not include which of the following?

• A. Chlorophyll e
• B. Chlorophyll b
• C. Chlorophyll c
• D. All of these options✓

Explanation: Bacteria use bacteriochlorophylls in photosynthesis without the production of energy. Bacteria only use bacteriochlorophylls for capturing light. Bacteriochlorophylls don't include chlorophyll e, b or c.

Q84. The cell organelles involved, in some cases, with extra-cellular digestion _ .

• A. Golgi complex
• B. Lysosomes✓
• C. Peroxisomes
• D. Glyoxysomes

Explanation: Lysosomes function as the digestive system of the cell, serving both to degrade material taken up from outside the cell and to digest obsolete components of the cell itself.

Q85. All of the following is true about bacilli bacteria except?

• A. All bacilli are gram-positive
• B. All bacilli are aerobic
• C. All bacilli are rod-shaped
• D. Both A and B✓

Explanation: Option D is correct because the question mentions to mention the incorrect options and both options A and B are incorrect about bacilli.

Q86. Oxidation number of Nitrogen in HNO3, is:

• A. +4
• B. +2
• C. +6
• D. +5✓
• E. +7

Explanation: Oxide ion has a charge of -2. Three oxide ion will thus have a charge of -6H has a charge of +1.N is HNO3 will thus be:-6+1+x=0x=+5.

Q87. If the difference between electronegativity values between two atoms is less than 1.7 , the bond is necessarily:

• A. Ionic
• B. Covalent✓
• C. Electrovalent
• D. Polar
• E. Non - polar

Explanation: If the electronegative difference is >1.7 then its nature is ionic and <1.7 then its nature is covalent and if its equal to 1.7 then nature of bond will be 50% ionic and 50% covalent.

Q88. For the reaction, A(g) -> products: When the concentration of A(g) doubles, the rate of reaction increases four folds, which means it is:

• A. Negative order reaction
• B. First order reaction
• C. Zero order reaction
• D. Second order reaction✓

Explanation: In second-order reactions, the rate of reaction is directly proportional to the square of the concentration of the concerned reactant. In this scenario, when we doubled the concentration of A, the rate increases four folds implying 'A' to be of the second order.

Q89. The thermal energy at constant pressure is called:

• A. Enthalpy✓
• B. Internal Energy
• C. Heat capacity
• D. Work done

Explanation: Chemical reactions are generally carried out at constant pressure (atmospheric pressure) and the heat of reaction at constant pressure is called Enthalpy (H) as shown by the equation: H = U + PV where H is the Enthalpy, U is the internal energy of the system, P is the Pressure which is to be held constant, and V is the volume.

Q90. One Calorie is equal to:

• A. 4.18 KJ
• B. 4.18 J✓
• C. 0.418 KJ mol-1
• D. 0.418 KJ

Explanation: 1 cal equals 4.18 J. It is very often confused with 1 Kcal which equals to 4.18 KJ

Q91. According to the general gas equation, density of an ideal gas depends upon:

• A. Pressure
• B. Temperature
• C. Molar Mass
• D. All of these✓

Explanation: According to the ideal gas law Density = pM / RT where p represents Pressure, M is for the Molar mass, R is the Ideal gas constant and T is the Temperature. The equation presented above is derived from the standard equation that is; pV=nRT where n is the number of moles of the gas.

Q92. Which of the following substances has giant covalent structure?

• A. Iodine crystal
• B. Solid CO2
• C. Silica✓
• D. White phosphorus

Explanation: Silica has tendency to form long chain covalent structure such as carbon so it has giant covalent structure.Diamond and graphite (forms of carbon) and silicon dioxide (silica) are examples of giant covalent structures (lattices) of atoms. All the atoms in these structures are linked to other atoms by strong covalent bonds and so they have very high melting points.

Q93. For a given mass of gas, if the pressure is reduced to half and its temperature is doubled, then volume V will become?

• A. 4V✓
• B. 2V2
• C. V/4
• D. 8V

Explanation: According to the formula PV=nRT, The pressure becomes p/2 and the temperature becomes 2T. Therefore the increase in volume will be 4V.

Q94. Which two elements are isotopes?

• A. 16X8 and 16Y8
• B. 14X8 and 15Y8✓
• C. 18X9 and 20Y10
• D. 12X6 and 12Y7

Explanation: In option A, both elements are the exact same, as they have same proton number (8) and same mass number (16) so, they are not isotopes (which vary in mass number but have the same proton number).Option B describes isotopes, as they have the same proton number (8), while having differing mass numbers.Option C describes two different elements entirely as they have varying proton numbers.Option D also describes two different elements due to varying proton numbers.

Q95. The given diagram shows the enthalpy changes during a chemical reaction.

• A. An endothermic reaction
• B. An exothermic reaction✓
• C. An isothermic process
• D. A non-spontaneous process

Explanation: This diagram shows a reaction in which the reactants are at a greater energy level than the products, indicating that energy is released during the reaction, i.e. change in enthalpy or (H2-H1) would be negative, indicating that it is an exothermic reaction so, option B is correct.Option A describes an endothermic reaction which would have a diagram depicting products, at a higher energy level than the reactants.Option C indicates a process in which the heat energy of the system does not change, but the diagram itself shows a change in enthalpy.Option D cannot be determined from a mere energy diagram as shown.

Q96. The relationship between Kp and Kc is given by?

• A. Kc=Kp(P/N)∆n
• B. Kc=Kp(P)∆n
• C. Kp=Kc(RT)∆n✓
• D. Kc=Kp(RT)∆n

Explanation: The relation between K and K is given by Kp = Kc (RT)∆n

Q97. Natural gas in homes burns in excess of oxygen, what is the limiting reactant in this case?

• A. Oxygen
• B. Natural gas✓
• C. Air
• D. There is no limiting reactant

Explanation: Natural gas is obviously the limiting reactant when the gas is burning in excess of oxygen.

Q98. The atomic mass, molecular mass, ionic mass or formula mass of a substance expressed in grams is called:

• A. Mole of a substance✓
• B. Weight of substance
• C. Mass of substance
• D. Molar mass of substance

Explanation: The atomic mass, molecular mass, ionic mass or formula mass of a substance expressed in grams is called mole of substance. Mole of the substance is expressed in grams. Molar mass is exrpressed in grams per mole.

Q99. What assumptions are made in the Kinetic Theory about an ideal gas? There are no forces of attraction between molecules the molecules are in a state of continuous random motion the size of the molecule is negligible

• A. I ONLY
• B. II ONLY
• C. I AND II ONLY
• D. II AND III ONLY
• E. I, II, III✓

Explanation: According to Kinetic Molecular Theory , there are no attractive forces between the molecules of a gas because the distance between them is very large. The gaseous molecules are in continuous random, zigzag motion called Brownian motion. Gaseous molecules have negligible sizes as compared to liquids and solids. As all the three statements are true hence , option E is the correct answer.

Q100. A liquid crystalline state exists between two temperatures i.e melting temperature and _ temperature.

• A. boiling
• B. freezing
• C. clearing✓
• D. all of these

Explanation: So, a liquid crystalline state exists between two temperatures i.e. melting temperature and clearing temperature. The property of liquid crystals is intermediate between those of crystals and isotropic liquids. That is why they are called liquid crystals or mesomorphic states.

Q101. Rate determining step of a chemical reaction which occur in more than one step depends upon the

• A. fastest step
• B. Slowest Step✓
• C. catalyst used
• D. Temperature of reaction

Explanation: Explanation Rate determining step of a chemical reaction which occur in more than one step depends upon the slowest step.

Q102. Nitrogen has the atomic mass of 7.Which of the following electronic configurations is of a Nitrogen atom in ground state?

• A. 1s2, 2s2, 2px1, 2py1, 2pz1✓
• B. 1s2, 2s2, 2px2, 2pz1
• C. 1s2, 2s2, 2px2, 2py1
• D. 1s2, 2s2, 2py2, 2pz1

Explanation: The electronic configuration of Nitrogen is as follows: 1s2, 2s2, 2p3. The 'Auf-bau principle' states that electrons fill lower-energy atomic orbitals before filling higher-energy ones. Moreover, we have the 'Hund's Rule' stating that when electrons occupy degenerate orbitals (i.e. of the same energy level), they must first occupy the empty orbitals before double occupying them.

Q103. The shielding effect is also called?

• A. Zee effect
• B. Screening effect✓
• C. Negative effect
• D. Reducing effect

Explanation: The shielding effect is the reduction in the effective nuclear charge on the electron cloud, due to differences in the attraction forces between electrons and the nucleus. The shielding effect is also known as the 'Screening Effect'. Hence, there is no difference between these two terms. They primarily mean the same thing.

Q104. A mole of a substance contains _ particles.

• A. 6.2x1022
• B. 6.22x1022
• C. 6.02x1023✓
• D. 6.5x1022

Explanation: Answer: C One mole contains an Avogadro’s number of particles i.e. 6.02x1023

Q105. The boiling point of water is higher than other hydrides because water molecules can form:

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

Explanation: Intermolecular hydrogen bonding is responsible for the high boiling point of water (100 °C) compared to the other group 16 hydrides that have no hydrogen bonds. For example if we take comparison of fluorine and H20,Fluorine is more electronegative than Oxygen, so technically, HF should engage in more hydrogen bonding than water. But the situation is different. Each HF molecule possesses three lone pairs of fluorine and one hydrogen. HF molecules on average make two hydrogen bonds. Each H2O molecule possesses two lone pairs of oxygen. H2O molecules are thus able to form an average of four hydrogen bonds. Hence, water molecules take part in more hydrogen bonding than Hydrofluoric acid. Water molecules form a bulky molecule and it is very difficult to break its bonds. To break all its bonds, a large amount of the energy is required. Thus, H2O has a higher boiling point than HF. Thus h20 can form four hydrogen bonds.

Q106. Lithium and beryllium are unique in such a way that they have higher charge densities which produce strong polarizing effects due to:

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

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

Q107. Common name of Octadecanoic acid is:

• A. Propionic acid
• B. Stearic acid✓
• C. Palmitic acid
• D. Formic acid
• E. Acetic acid

Explanation: Stearic acid (IUPAC systematic name: octadecanoic acid) is one of the useful types of saturated fatty acids that comes from many animal and vegetable fats and oils.

Q108. ......is a technique to separate impurities from chemical products:

• A. Lands Berger's method
• B. Fractional crystallization✓
• C. Beckmann method
• D. None

Explanation: As the solution cools, the solubility of the compound (and of the soluble impurities) decreases, the solution becomes saturated with the desired compound, and the compound begins to crystallize. Removing the solution from the crystals thus removes the solvent and the soluble impurities from the desired crystals.

Q109. The densities of liquids are much _ than gases but _ to solids.

• A. smaller, closer
• B. greater, closer✓
• C. smaller, far away
• D. greater, far away

Explanation: The densities of liquids are much greater than gases but closer to solids. In the case of solids, the molecules are tightly packed and hence large mass is concentrated on less volume. Hence, the density becomes higher. But in cases of liquids and gases, their molecules have intermolecular space, and hence their large mass is not concentrated in a small volume. So the density of solids is generally more than that of liquids and gases.

Q110. Amorphous solids turns into glass like state from rubber like state, this is called

• A. transition
• B. crack transition
• C. glass transition✓
• D. all of these

Explanation: The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rubbery state as the temperature is increased.

Q111. The variation in physical properties of a crystal due to direction is called

• A. isotropy
• B. entropy
• C. anisotropy✓
• D. none of these

Explanation: Anisotropy is the property of a material that allows it to change or assume different properties in different directions, as opposed to isotropy. It can be defined as a difference, when measured along different axes, in a material's physical or mechanical properties.

Q112. Which ion will have a maximum value of the heat of hydration?

• A. Al+3✓
• B. Cs+
• C. Ba+
• D. Mg+2

Explanation: The heat of hydration depends upon the charge to size ratio of the ions. Since the charge of the 'Al ion' is the greatest, it has the maximum hydration energy

Q113. All are enzymes involved in fermentation process except one:

• A. Zymase
• B. Invertase
• C. Lipase✓
• D. Diastase

Explanation: Lipase is an enzyme that breaks down lipid molecules. Fermentation does not involve lipid substances to be broken down, hence lipase has no use in fermentation.

Q114. Following has IUPAC name of:

• A. 2, 3 - tetramethyl butane
• B. 2, 2, 3, 3 - tetramethyl pentane✓
• C. 3, 3, 4, 4 - tetramethyl butane
• D. 3, 4 - bis (dimethyl butane)

Explanation: The longest carbon chain in the compound above is of five carbons as shown in the figure below, hence the correct option must have a “pent” mentioned, which is the case for B only. Moreover, as we have 4 methyl side chains, equally distributed on carbons 2 and 3, we will mention the carbon number on which the chains are present. The numbers in the IUPAC name must equal the number of side chains hence we have 4 numbers present at the start of the name of the molecule corresponding to the number of side chains present.

Q115. In alkanes, each carbon has hybridization:

• A. sp3✓
• B. sp
• C. sp2
• D. dsp

Explanation: The carbon atoms in alkanes are sp3 hybridized, and have tetrahedral shapes, with the bonded atoms at angles of 109.5° to each other. Free rotation is possible around the carbon-carbon single bonds in alkanes, making the carbon chains very flexible and "floppy" — particularly for the larger molecules.

Q116. Secondary alcohol is the product of reduction of which carbonyl compound?

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

Explanation: Reduction of ketones gives secondary alcohols. The acidic work-up converts an intermediate metal alkoxide salt into the desired alcohol via a simple acid base reaction.

Q117. Which of the following has the lowest vapour pressure at 20 degrees Centigrade?

• A. Diethyl ether
• B. Chloroform
• C. Carbon tetrachloride
• D. Water✓

Explanation: The boiling point of a substance is a measure of the strength of the intermolecular forces between the molecules of the substance. The stronger the intermolecular forces, the higher the boiling point. Water has strong hydrogen bonding interactions between the molecules, which is why it has the highest boiling point.The vapor pressure of a substance is the pressure exerted by the vapor of the substance above the liquid. The lower the vapor pressure, the less likely the molecules of the substance are to evaporate. Water has a low vapor pressure at 20 degrees Centigrade because the strong intermolecular forces make it difficult for the molecules to escape from the liquid.The other three substances, diethyl ether, chloroform, and carbon tetrachloride, have weaker intermolecular forces than water. This is why they have lower boiling points and higher vapor pressures at 20 degrees Centigrade.Therefore, water has the lowest vapor pressure at 20 degrees Celsius among the substances provided.,

Q118. Ketone reacts with Grignard reagent to form _ in acidic media?

• A. Tertiary alcohol✓
• B. isopropyl alcohol
• C. primary alcohol
• D. carboxylic acid

Explanation: Ketone contains a carbonyl group at the centre . The oxygen is attached to carbonyl carbon via a double bond .When it reacts with a grignard reagent (RMgX), the double bond breaks and and just a single bond is left behind with carbon , while oxygen gets bonded to Hydrogen. Thus a hydroxyl group is formed at the central carbon, and a tertiary alcohol is formed.Following reaction between Acetone and Grignard reagent could help understanding the mechanism:

Q119. What would be the major product of the following reaction?

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

Explanation: The given reaction is Friedel Craft Acylation. Given C2H5OCl in the presence of AlCl3 leads to the addition of C2H5O to the benzene ring. Since, CH3 is an ortho-para directing group. It leads to the addition of substances at ortho-para positions, which are (2,4) positions. So there is an addition of C2H5O at either of ortho or para position.

Q120. Reagent used to reduce a carboxylic acid to an alkane is:

• A. Ni / H2
• B. NaBH4
• C. P / HI✓
• D. LiAlH4

Explanation: Hot red Phosphorus and Hydrogen Iodide at 200℃ is used to reduce carboxylic acids to alkanes according to the equation below, using propionic acid as an example: C2H5COOH + 6HI —---------------------> C3H8 + 2H2O + 3I2 Therefore option C is correct.

Q121. Which of these in an aqueous solution of equal concentration has the lowest pH?

• A. Chloroethanoic acid✓
• B. Ethanoic acid
• C. Ethylamine
• D. Phenol

Explanation: Chloroethanoic acid (ClCH2COOH) is a stronger acid than the other options due to the electron-withdrawing effect of the chlorine atom, which stabilizes the negative charge on the conjugate base (ClCH2COO-). This stabilization makes it easier for the acid to donate a proton (H+ ion) and results in a lower pH in an aqueous solution of equal concentration compared to the other options.

Q122. By treating CO2 with Grignard’s reagent, the following compound is obtained;

• A. Aromatic compounds
• B. Alcohols
• C. Carboxylic acid✓
• D. Ethers

Explanation: When carbon dioxide (CO₂) reacts with a Grignard reagent (RMgX), a carboxylic acid is formed. The Grignard reagent acts as a nucleophile, attacking the electrophilic carbon in CO₂. After the addition of the Grignard reagent, the intermediate is hydrolyzed, resulting in the formation of a carboxylic acid and a magnesium salt.

Q123. The IUPAC name of the following compound is:

• A. 1-Ethyl-2, 4-dimethlycyclohexane✓
• B. 2-Ethyl-1,4-dimethylcyclohexene
• C. 2-Ethyl-1, 1-dimethylcyclohexane
• D. 4-Ethyl-1, 2-dimethylcyclohexane

Explanation: The IUPAC name of the compound is 1-ethyl-2,4-dimethylcyclohexane. The parent compound is cyclohexane. The carbon to which ethyl is attached is considered carbon 1 according to alphabetical order. The two methyl groups are on carbon 2 and 4 respectively.

Q124. Which of the following compounds possesses a single covalent bond between carbon and hydrogen?

• A. CH4
• B. C2H2
• C. C2H4
• D. All of the above✓

Explanation: All of the compounds contain a single covalent bond between carbon and hydrogen atoms. Only that C2H2 and C2H4 contain triple and double bonds between carbon atoms respectively.

Q125. Impurities of lead in silver are removed by:

• A. Parke’s process✓
• B. Solvay process
• C. Cyanide process
• D. Amalgamation process

Explanation: The Parke's process is a pyrometallurgical industrial process for removing silver from lead during the production of bullion. It is an example of liquid extraction, hence A. The process takes advantage of two liquid-state properties of zinc. The first is that zinc is immiscible with lead and the other is that silver is 3000 times more soluble in zinc than it is in lead. The Solvay process is used to produce sodium carbonate.

Q126. Chromium dissolves in dilute H2SO4 for [Cr(H2O)6]2. The colour of the ion is:

• A. Blue✓
• B. Yellow
• C. Brown
• D. Pink

Explanation: The valence shell electronic configuration of Cu+2 ions is 3d9 Hence, aqueous Cu+2 ions are blue in colour,It contains 1 unpaired electron. VIDEO EXPLANATION .

Q127. Catenation is a process in which carbon shows the properties of:

• A. Making single bond
• B. Hybridization
• C. Making chains or rings of carbon atoms✓
• D. Isomerism
• E. Breaking of bonds

Explanation: Catenation is the process by which an atom is able to form a bond with another atom of its kind. Carbon possesses this ability hence is able to form ringed structures.

Q128. EDTA ion is a _ ligand.

• A. Monodentate
• B. Bidentate
• C. Tridentate
• D. Polydentate✓
• E. None of the above options are correct

Explanation: EDTA ion is polydentate. Ethylenediaminetetraacetic acid (EDTA) is an amino polycarboxylic acid with the formula [CH2N(CH2CO2H)2]2. This white, water-soluble solid is widely used to bind to iron and calcium ions. It binds these ions as a hexadentate ("six-toothed") chelating agent.

Q129. If products of a reaction act as a catalyst, such process is called:

• A. Positive catalyst
• B. Negative catalyst
• C. Auto catalyst✓
• D. Both A and B

Explanation: If a product of the reaction acts as a catalyst, then such a catalyst is called an autocatalyst.

Q130. The only o, p−directing group which is deactivating in nature is:

• A. -NH2
• B. -OH
• C. -X (halogens)✓
• D. -R (alkyl groups)

Explanation: Halides are ortho-para- directing groups but unlike most ortho-para- directors halides tend to deactivate benzene. This unusual behaviour can be explained by two properties:1. Since the halogens are very electronegative they cause inductive withdrawal (withdrawal of electrons from the carbon atom of benzene).2. Since the halogens have non-bonding electrons they can donate electron density through pi bonding (resonance donation).Option C is correct.

Q131. Which alkyl halide has the lowest reactivity for a particular alkyl group?

• A. R-CI
• B. R-F✓
• C. R-Br
• D. R-I

Explanation: To react with the alkyl halides, the carbon-halogen bond has gotten to be broken. Because that gets easier as you go from fluorine to chloride to bromide to iodide, the compounds get more reactive in that order. Iodoalkanes are the most reactive and fluoroalkanes are the least.

Q132. The compound ‘leaf alcohol’ is partly responsible for the smell of new - mown grass CH3CH2CH=CHCH2CH2OH Leaf alcohol Which two compounds will be formed when ‘leaf alcohol’ is oxidized using hot, concentrated manganate (VII) ions?

• A. CH3CO2H and HOCH2CH2CH2CO2H
• B. CH3CO2H and HO2CCH2CH2CO2H
• C. CH3CH2CO2H and HO2CCH2CO2H✓
• D. CH3CH2CO2H and HOCH2CH2CO2H

Explanation: The answer is C as when the double bond breaks, based on the structure of both the carbons involved in the double bond, each having a hydrogen attached alongside an organic chain, aldehydes would be formed. Both the aldehydes would be oxidized to give carboxylic acid. CH3CH2COOH is formed plus COOHCH2CH2OH with the latter being a primary alcohol. It would be further oxidized to give a dicarboxylic acid which is HOOCCH2COOH, thus the answer is C.

Q133. Rectified spirits have a percentage of alcohol.

• A. 12 %
• B. 24 %
• C. 95 %✓
• D. 100 %

Explanation: The purity of rectified spirit has a practical limit of 95% ABV (95.6% by mass) when produced using conventional distillation processes, as a mixture of ethanol and water becomes a minimum-boiling azeotrope at this concentration.

Q134. The test used to distinguish among primary, secondary, and tertiary alcohols is:

• A. 2,4 - DNPH test
• B. Tollens test
• C. Lucas Test✓
• D. Fehling solution test

Explanation: Lucas' Solution is a solution of anhydrous ZnCl and concentrated HCl and we use this solution to examine the class of alcohol that we are dealing with. The difference is present between the time taken for the alcohol to convert into chloroalkane. This change is marked by the solution becoming milky white from colourless and also an oily layer is formed on the surface of the solution during the reaction by the chloroalkane formed. Tertiary alcohols show the results almost immediately, followed by secondary alcohols showing results between 3-5 minutes. The primary alcohols do not show a result unless heated. 2,4 - DNPH is a test for the detection of aldehydes and ketones. Tollens and Fehling Solution are used to differentiate between an aldehyde and ketone. Only Aldehydes gives Tollens and Fehlings tests.

Q135. What is the name of CH3CH2CH=CHCH2CH=CHCH3 ?

• A. 2,3-octadiene
• B. 2,4-octadiene
• C. 2,5-octadiene✓
• D. 2,5-octadyne

Explanation: The parent chain is 8 carbons long so it is -octa and diene because of the 2 double bonds. Also the position of these double bonds is correctly indicated in option C.

Q136. Which of the following statement is correct about the Avogadro's constant?

• A. It is the mass of one mole of any element
• B. It is the mass of 6.023×10^23 atoms of any element
• C. It is the number of atoms in one mole of neon✓
• D. It is the number of atoms in 12g of any element

Explanation: Avogadro's constant defines the number of atoms present in one mole of any substance including neon. So option C is the most suitable answer.

Q137. Select the group whose elements easily lose electrons.

• A. IA✓
• B. VA
• C. VIA
• D. VIIA

Explanation: Group 1-A elements being the most electropositive easily loose electrons that’s why they are called reducing agents and alkali metals. So, option A is correct.

Q138. 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.

Q139. An object is moving along a circular path of radius 4m. What will be its angular displacement if it moves 14m on this circular path?

• A. 5.5 radians
• B. 5.0 radians
• C. 3.5 radians✓
• D. 4.5 radians

Explanation: Explanation is given below: To find the angular displacement of an object moving along a circular path, you can use the following formula: Angular Displacement (θ) = arc length (s) / radius (r) In this case, the object is moving 14 meters along a circular path with a radius of 4 meters. θ = 14 m / 4 m θ = 3.5 radians So, the angular displacement of the object is 3.5 radians.

Q140. Which of the following gives the relationship between linear velocity and angular velocity?

• A. v=rω✓
• B. v=sω
• C. v=rθ
• D. v=sθ

Explanation: Explanation is given below: Here, v = linear velocity, r = radius and ω= angular velocity.

Q141. The period of circular motion is

• A. y=2π/ω✓
• B. y=2πω
• C. y=ω/2π
• D. y=πω/2

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

Q142. A particle of mass m at rest is acted upon by a force F for a time t. Its K.E after an interval t is

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

Explanation: The explanation of this question will be added soon.

Q143. If the speed of an object is tripled, its kinetic energy is increased by:

• A. 1/9 times
• B. 1/3 times
• C. 6 times
• D. 9 times✓

Explanation: K.E = 1/2 x m x v2 If mass remains constant, then K.E ∝ v2 So, if speed is tripled, then K.E' ∝ (3)2 = 9 K.E' / K.E = 9 / 1 K.E' = 9 K.E K.E will increase by 9 times.

Q144. A sound wave of frequency f and wavelength λ travels through air. It may be assume that its speed is independent of the frequency. Which graph correctly shows the variation off with λ?

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

Explanation: Explanation is given below.

Q145. A whistle giving out 450 Hz approaches a stationary observer at a speed of 33m/s. The frequency heard by the observer in Hz is (speed of sound = 330m/s).

• A. 409
• B. 429
• C. 517
• D. 500✓

Explanation: v' = v/(v — vs) x v v' = 330/(330-33) x 450 =500 Hz

Q146. Angle between radius vector and centripetal acceleration is

• A. 0°
• B. π✓
• C. 2π
• D. none of these

Explanation: Consider a particle P is moving along a circle with centre as origin as shown in figure .For any position of P in the path the radius vector lies along OP and directed towards the particle. So the centripetal acceleration and radius vector are exactly directed opposite to each other at any position of the particle along the path. So the angle between centripetal acceleration and radius vector is 180 degrees which is equal to in radians.

Q147. A spring of force constant 800 N/m has an extension of 5 cm, the work done in extending it from 5 cm to 15 cm

• A. 16 J
• B. 8 J✓
• C. 32 J
• D. 24 J

Explanation: Work done is found using the formula = ½ x k x [(extension 1)^2 - (extension 2)^2]= ½ x 400 x [(0.15)^2 - (0.05)^2]= 8 J

Q148. Heat exchanged between the system and surrounding at constant volume is shown by the relation?

• A. ΔH= qv+ w
• B. ΔE=(q)v✓
• C. ΔH=(q)v
• D. ΔE=(q)v + PV

Explanation: Since we have a constant volume, it is safe to assume that no work is being done on the system, or by the system. Hence the change in Energy, E, of the system, would be equal to the heat supplied to the system, q, keeping the volume, v, constant.

Q149. A vibrating string has a little sound. However, when attached to a board the sound has a greater intensity. This is because?

• A. The string vibrates with more energy
• B. The sound is concentrated over smaller area
• C. The speed of sound is greater in board
• D. The energy leaves the board at a greater rate✓

Explanation: A vibrating string has a little sound. However, when attached to a board the sound has a greater intensity. It is because The energy leaves the board at a greater rate.

Q150. When a stone is thrown horizontally with 2 m/s from a building of height 5 m then just before hitting the ground its acceleration is:

• A. 12 m/s2
• B. 13 m/s2
• C. 9.8 m/s2✓
• D. 7.6 m/s2

Explanation: The acceleration of the stone just before hitting the ground will be approximately 9.8 m/s². This is because the stone experiences only the acceleration due to gravity in the vertical direction, which is 9.8 m/s² downward.

Q151. Which of the given motion is a type of 2D motion

• A. Circular
• B. Pendulum motion
• C. Projectile motion
• D. All of these✓

Explanation: Option A : Circular motion is 2D motion . Option B : Motion of Pendulum is 2D motion . Option C : Projectile motion is 2D motion . All of the following are projectile motions. So , we will choose option D i.e all option are correct .Option : D All the given motions are 2D motions . Circular, pendulum as well as projectile motion are 2D motion . So , all of these are correct.

Q152. Centrifugal acceleration of a car moving around in a circle of radius 5 m with 10 m/s velocity is _.

• A. 20 m/s2✓
• B. 10 m/s2
• C. 6 m/s2
• D. 11 m/s2

Explanation: Correct option:AAs we know by the formula a = v²/r where v is the velocity and r is the radius of the circle.Putting values in the above formulaa = (10m/s)2/5ma= 100m²/s2/5m a=20m/s²

Q153. The wave in which crest and trough superimpose each other is ?

• A. Sound wave
• B. Light wave
• C. Stationary wave✓
• D. All of these

Explanation: Stationary waves, also known as standing waves, are formed by the combination of two waves with the same frequency and amplitude, moving in opposite directions. When these waves superimpose at some points, the energy is added. For instance, if a crest is superimposed by a crest, or a trough is superimposed by a trough, an antinode is observed. Alternatively, at some points, the energies may be canceled out/ For instance, a crest can be superimposed by a trough or vice versa, forming a node.

Q154. If two equal forces act perpendicularly upon each other, then the angle between the resultant force and a horizontal surface will be

• A. 0°
• B. 30°
• C. 45°✓
• D. 60°

Explanation: When two equal forces are applied perpendicularly to each other, they create a right angle. In such a case, the resultant force can be determined using the Pythagorean theorem. The magnitude of the resultant force is equal to the square root of the sum of the squares of the magnitudes of the two forces. Since the two forces are equal, their magnitudes are the same. Therefore, if we consider each force to have a magnitude of "F," the magnitude of the resultant force will be: Resultant force = √(F^2 + F^2) = √(2F^2) = √2F Now, when the resultant force is resolved into horizontal and vertical components, each component will have a magnitude of √2F. Since the vertical component is equal to the force acting vertically, the angle between the resultant force and the horizontal surface will be 45 degrees. Therefore, the correct option is C, 45 degrees.

Q155. 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).

Q156. An emf of 0.003V is induced in a wire when it moves at right angles to uniform magnetic field with a speed of 4m/s if the length of the wire in the field is 15cm, what is the flux density in tesla?

• A. 0.003
• B. 0.005✓
• C. 6
• D. 12

Explanation: Explanation is given below:

Q157. The induced emf in a coil is proportional to:

• A. Magnetic flux through the coil
• B. Rate of change of magnetic flux through the coil✓
• C. Area of the coil
• D. Product of magnetic flux and area of the coil

Explanation: Among the options given, the correct answer is A) Rate of change of magnetic flux through the coil. This change induces an electromotive force in the coil according to Faraday's law of electromagnetic induction.

Q158. The work function of a metal is 1 eV. Light of wavelength 3000 Å is incident on this metal surface. The velocity of the emitted photo-electrons will be:

• A. 10 m/sec
• B. 1x103 m/ sec
• C. 1x104 m/ sec
• D. 1x106 m/ sec✓

Explanation: This is the following solution:

Q159. If an electron is accelerated through a potential difference of 54 volts, its de broglie wavelength will be:

• A. 1.66 x 10-8 m
• B. 1.66 x 10-10 m✓
• C. 1.66 x 10-9 m
• D. 1.66 x 10-12 m

Explanation: Option B is correct.Given data: h=6.63 x10^-34 Js, m=9.1x1 10^-31 kg, q= 1.6x10^-19 J ,V=54 vFind out: λ =?Solution ;Weknow thatλ =h/√2meV6.63 x10-34/ √ 2(9.1x1 10-31) (1.6x10-19)(54)1.66x10^-10 m

Q160. The direction of current through the load resistance of a full-wave rectification circuit:

• A. remains constant✓
• B. inverts for positive cycle
• C. changes for every cycle
• D. inverts for negative cycle

Explanation: Rectification changes alternate current to direct current where current remains positive throughout the cycle.

Q161. Find the resistance if the voltage of a circuit is 45 volts and current is 30 Amperes?

• A. 1.6 Ohms
• B. 1.5 Ohms✓
• C. 1.7 Ohms
• D. 1.8 Ohms

Explanation: We know that V = IR Rearranging this formula gives: R= VI = 45/30 = 312 = 1.5 Ohms As it is numerical so it can have only one possible answer.

Q162. The frequency of applied AC is 2 kHz. Its time period will be:

• A. 0.5 x 10-3 sec✓
• B. 0.5 second
• C. 5 sec
• D. 2 sec

Explanation: Formula: Frequency = 1/t t = 1/2000= 0.5 x 10-3 sec

Q163. The output voltage of a rectifier is:

• A. Smooth
• B. Pulsating✓
• C. Perfectly direct
• D. Alternating

Explanation: A rectifier is used to convert alternating current to pulsating direct current not smooth direct current. Perfectly direct current will have fixed magnitude and fixed direction of current. This is not true for the output of a rectifier. Hence, option B is correct.

Q164. Which of the following has zero average value in a plane electromagnetic wave:

• A. kinetic energy
• B. magnetic field
• C. electric field
• D. both (b) and (c)✓

Explanation: In an electromagnetic wave, the average value of the electric field or magnetic field is zero, because electromagnetic waves are sinusoids and the average of a sinusoid over 1 period is zero.

Q165. Find the wavelength of electromagnetic waves of frequency 3x1012 Hz in free space.

• A. 10-4 m✓
• B. 104 m
• C. 10-2 m
• D. 102 m

Explanation: This is the following solution:

Q166. In the circuit given below, v(t) is the sinusoidal voltage source, voltage drop VAB(t) across the resistance R is, diode D1 and D2 are identical

• A. Full wave rectified
• B. No rectification and has the same peak value in the positive and negative half cycles✓
• C. No rectification and has different peak values during positive and negative half cycle
• D. Half wave rectified

Explanation: Direction of current is opposite through R for positive and negative half cycles so output is not rectified. Since R1 and R2 are same. Hence, the peaks during positive half and negative half of the input signal will be same.

Q167. Some ice, at its melting point, is added to m kg of water at an initial temperature of 290 K. c is the specific heat capacity of water and L is the latent heat of fusion of ice. The ice melts completely. The final temperature of the water is "273 K". What is the minimum mass of ice that is required?

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

Explanation: For Specific heat capacity, use the formula Q = mcΔT.And for the latent heat of fusion of ice, use the formula Q = ML.The heat that is taken by the ice for it to melt is equal to the heat lost by the water.Energy gained by ice = energy lost by the water.ML = mcΔT.ML = mc(290K - 273K).ML = mc x 17.Then we divide through by L.M = 17 mc/L.Please note that the 273K that we have used in this solution is the temperature at which water freezes.Therefore the minimum mass of required ice is = "17 mc/L".

Q168. The resistivity of a wire is _ ohm-m if 0.75 A current flows through it by applying 1.5 V potential difference, take length and cross-section as 5m and 2.5 x 10^-7 m^2.

• A. 1 x 10^-7✓
• B. 2.63 X 10^-8
• C. 19 X 10^-8
• D. 7.85 x 10^-8

Explanation: For resistivity , first we have to find out resistance V = I R So R = V / I R = 1.5 / 0.75 R = 2 ohms R = l / A = resistivity length / area = R A / l = 2 2.5 x 10-7 / 5 = 1 x 10-7 ohm-m

Q169. Electron charge in accelerating motion will produce _.

• A. Electric field
• B. Magnetic field
• C. EM waves✓
• D. None of these

Explanation: Correct Option:CThis option is correct because accelerating charges produces changing electric fields and magnetic fields.Changing electric fields produces magnetic fields and changing magnetic fields produces electric fields.This interplay between induced electric field and magnetic field leads yo propagating electromagnetic waves

Q170. In compton׳s scattering process , wavelength of scattered X-rays :

• A. Remains same
• B. Increases✓
• C. Decreases
• D. None of these

Explanation: In Compton's scattering process, the wavelength of scattered x-ray increases. Compton scattering is a type of scattering of electromagnetic radiation by a charged particle, usually an electron. In this process, a photon (x-ray) collides with an electron, and the photon transfers some of its energy and momentum to the electron. As a result, the photon's wavelength increases, and its frequency decreases. The change in wavelength is given by the Compton formula: Δλ = h/mc * (1 - cosθ), where Δλ is the change in wavelength, h is Planck's constant, m is the mass of the electron, c is the speed of light, and θ is the angle between the incident photon and the scattered photon.

Q171. Capacitance is given by:

• A. C = εₒA/d✓
• B. C = dA/εₒ
• C. C = d/Aεₒ
• D. C = dεₒ/A

Explanation: The capacitance of a parallel plate capacitor is directly proportional to the area of the plates (A) and the permittivity of free space (εₒ). It is inversely proportional to the distance (d) between the two plates. Hence, capacitance is given by: C = εₒA/d.

Q172. Force exerted by a unit charge is called:

• A. Electric field intensity✓
• B. Magnetic field
• C. Magnetic flux
• D. Charge

Explanation: The electric field intensity at any point in the field is defined as the force per unit charge at that point. Mathematically, it is represented as E = F/q. Its unit is NC⁻¹.

Q173. Electric potential determines the flow of?

• A. Atom
• B. Molecule
• C. Compound
• D. Charge✓

Explanation: Charge flows from higher to lower potential.

Q174. In parallel plate capacitor Capacitance depends on:

• A. Charge
• B. Electric field
• C. Voltage
• D. Cross-sectional area✓

Explanation: Capacitance in parallel plate capacitors depends upon the area of each plate, dielectric medium between the plates and the distance between them.

Q175. Ohm's law is valid at _ temperatures

• A. Constant✓
• B. Varying
• C. Low
• D. High

Explanation: Ohm’s law states that the voltage and current are directly proportional to each other provided temperature and other physical states remain constant.

Q176. Correct form of ohm's law

• A. I = VR
• B. V = I/R
• C. V = IR✓
• D. R= IV

Explanation: V=IR is the correct form of Ohm’s Law.

Q177. In an NPN transistor, the current IE that flows in the emitter circuit is:

• A. IC + IB✓
• B. IC - IB
• C. IC x IB
• D. Zero

Explanation: NPN transistors let the current flow from the emitter to the collector and base controls the flow of current through it. Therefore, IE = IC+IB.

Q178. Ratio of momentum of photons having wavelength 4000 angstrom and 8000 angstroms is?

• A. 2:1✓
• B. 1:2
• C. 20:1
• D. 1:20

Explanation: P=h/λ P1/P2 = λ2/λ1= 8000A/4000A = 2:1

Q179. Balmer series lies in that region of electromagnetic wave spectrum, which is known as:

• A. Visible region✓
• B. Ultraviolet region
• C. Invisible region
• D. lnfra-red region

Explanation: The Balmer series corresponds to the set of spectral lines in the emission spectrum of hydrogen atoms that result from electron transitions within the atom involving the principal quantum number "n" ranging from 3 to higher levels down to n = 2. These transitions result in the emission of photons with specific energies. The Balmer series is located in the visible region of the electromagnetic spectrum, which ranges from approximately 400 to 700 nanometers (nm). It includes colors that are visible to the human eye.

Q180. During a negative β-decay

• A. An atomic electron is ejected
• B. An electron which already present with in the nucleus is ejected
• C. A neutron in the nucleus decays emitting an electron✓
• D. A part of binding energy of nuclei is converted into electron

Explanation: When ratio of neutrons to protons is more than one, then neutrons convert into protons by emitting an electron. Electrons donot come out from nucleus as nucleus contains no electrons, therefore, neutrons in the nucleus decay converting into electron and emitting electron.

Q181. Which water is used to reduce the speed of fast moving neutrons?

• A. Salty water
• B. Pure water
• C. Heavy water✓
• D. Muddy water

Explanation: Heavy water (D2O) is often used as a moderator in nuclear reactors to slow down fast-moving neutrons. This is because heavy water contains deuterium, which has a larger atomic mass than hydrogen (the main component of regular water), and can therefore more effectively slow down fast-moving neutrons through collisions

Q182. Which surface will absorb more light?

• A. Yellow painted
• B. Blue painted
• C. White painted
• D. Black painted✓

Explanation: Dark, rough, and dull surfaces absorb radiation better than light, smooth, and shiny surfaces. Black surfaces have greater absorptivity,and hence,they absorb most of the light falling on it.

Q183. Beta-decay means emission of electron from:

• A. Radioactive nucleus✓
• B. Innermost electron orbit
• C. A stable nucleus
• D. Outer-most electron orbit

Explanation: A beta particle is emitted from the nucleus of an atom during radioactive decay.

Q184. In population inversion (Ruby Laser) atoms can reside in the excited state for:

• A. 10-11
• B. 10-8✓
• C. 10-3
• D. 10+3

Explanation: The electrons in ruby lasers reside in the excited state for 10 -8 seconds. The electrons then release radiationless energy to achieve the metastable state and reside there for 10 -3 seconds. This allows us to achieve population inversion. In a ruby laser, the atoms can reside in the excited state for a relatively long duration. The typical time for which the atoms can remain in the excited state in a ruby laser is on the order of microseconds (10^-8 seconds).

Q185. The induced emf will oppose the flux producing It Is according to:

• A. Gravitational law
• B. Coulomb law
• C. Newton's law
• D. Lenz's law✓

Explanation: Lenz's law states that the direction of the electric current induced in a conductor by a changing magnetic field is such that the magnetic field created by the induced current opposes changes in the initial magnetic field.

Q186. Eddy currents flow in:

• A. Open loops
• B. Closed loops✓
• C. Straight llnes
• D. Vertical loops

Explanation: Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to Faraday's law of induction or by the relative motion of a conductor in a magnetic field.

Q187. Spectral lines is like a ----- of absorbed or emission energy in a spectrum:

• A. Charged Pattern
• B. Fingerprint Pattern✓
• C. Discharged Pattem
• D. Scattered Pattern

Explanation: The pattern consists of discrete lines, therefore “fingerprint pattern” is the most suitable choice.

Q188. The black body always _ radiations:

• A. Emit
• B. Absorb
• C. Both Emit And Absorb✓
• D. Reflects

Explanation: A black body or blackbody is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. The name "black body" is given because it absorbs all colors of light. A black body also emits black-body radiation.

Q189. How many up quarks in proton:

• A. 1
• B. 2✓
• C. 3
• D. 4

Explanation: A proton is made up of two up quarks and one down quark.

Q190. An eagle of mass 4 kg is locked inside a cage of mass 2 kg. If the eagle starts flying, what will be the mass of the bird and cage assembly?

• A. 5 kg
• B. 7 kg
• C. 2 kg
• D. 6 kg✓

Explanation: Since the cage is at rest no pseudo force will be acting on the bird. Hence, the weight of bird will be 4kg in air, therefore weight of bird and cage assembly will be equal to 4kg and 2kg i.e equal to 6kg.

Q191. If the force of 20 N acts at an angle 60 degree along horizontal then its vertical and horizontal components are:

• A. 20 N, 0 N
• B. 15 N, 10 N
• C. 17.32 N, 10 N✓
• D. 10 N, 17.32 N

Explanation: Vertical component Fy= 20sin60= 17.32NHorizontal componentFx= 20cos60= 20 x 1/2 =10N

Q192. A gun fires a bullet of mass 40 g with a velocity of 1200 ms-1 . The man holding it can exert a maximum force of 144 N on the gun. How many bullets can he fire per second at the most?

• A. 1
• B. 2
• C. 3✓
• D. 4

Explanation: The man can exert a maximum force of 144N implies that this is the force that he can bear from the gun while the bullets are being fired. So the maximum force from the gun can be 144 N per sec. ∴F= nmv/t144= (n×0.04×1200 ) / 1⇒n=12/4 ​=3

Q193. From the following which word does not belong to the others:

• A. Index
• B. Book✓
• C. Glossary
• D. Chapter

Explanation: An index, glossary, and chapter are all parts of a book. Option A does not belong because the book is the whole, not a part.

Q194. Directions:In each of the following questions a statement is given, followed by two conclusions.Statement: "Please do not wait for me, I may be late, start taking lunch as soon as the guests arrive." - A message from a Director of a Company to his office managers.Assumptions:I. Keeping guests waiting is not desirable. II. Lunch may not be ready in time.

• A. Only assumption I is implicit✓
• B. Only assumption II is implicit
• C. Either I or II is implicit
• D. Both A and B

Explanation: The director instructs his managers not to keep the guests waiting because of him and to proceed with lunch soon after their arrival. This implies that lunch would be ready in time. So, only I is implicit. Hence, option A is accurate.

Q195. Statement: I. Large number of Primary Schools in the rural areas is run by only one teacher.II. There has been a huge dropout from the primary schools in rural areas.

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

Explanation: One teacher running a lot of schools leads to mismanagement and it lowers the educational standard which causes students to drop out from school in rural areas. So, option A is the most accurate answer.

Q196. Statement:According to reports, the childrens below age 10 are being aggressive because of mobile phones.Course of Action:I. Parents needs to be strict with their child.II. Parents need to be concerned and limit their screening time.

• A. Both of the courses of action follow
• B. None of the courses of action follow
• C. Only courses of action I follows
• D. Only courses of action II follows✓

Explanation: The root cause of children getting aggressive is their mobile phones hence limiting the time that children use their phones can solve this problem. Lenient parentage is not the problem plus strict parenting sometimes causes rebellious behavior.

Q197. Statements:Nutritious food is delicious and good for health. Apple is nutritious.Conclusions:(I) Apple is good for health.(II) Delicious foods are nutritious.

• A. Only conclusion (I) follows✓
• B. Only conclusion (II) follows
• C. Both conclusions follow
• D. Both of the conclusions do not follow

Explanation: An apple is nutritious and nutritious food is good for health hence apple is good for health. However not all delicious food is nutritious like chips so conclusion 2 is incorrect.

Q198. Statement:Should coal engines be replaced by electric engines in trains? Arguments:(I) Yes. Coal engines cause a lot of pollution.(II) Yes. Electric engines are good on performance, easy to operate, and low on maintenance.(III) No. Pakistan does not produce enough electricity to fulfill its domestic needs also.

• A. All arguments are strong
• B. Only arguments I and II are strong✓
• C. Only arguments II and III are strong
• D. Only arguments I and III are strong

Explanation: Coal engines are responsible for creating a huge amount of pollution in contrary to, electric engines. Also their performance, operation, and maintenance is easy as compared to electric engines. Arguments I and II seem to be true but argument III does not provide a convincing reason and hence does not hold strong.