Balochistan Mdcat Mock Paper 3 — Solved Past Paper with Answers

Q1. Choose the correct option.

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

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

Q2. Find errors in the following sentence:

• A. The captain, along with his team
• B. Are practising very hard✓
• C. For the
• D. Forthcoming matches

Explanation: The main subject of the sentence is 'the captain,' which is singular. The phrase 'along with his team' is a parenthetical expression and does not change the subject-verb agreement. Therefore, the verb should agree with the singular subject 'the captain,' requiring the use of 'is' instead of 'are.' This makes Option B incorrect because it uses 'are' instead of 'is.'Options A, C, and D do not contain any grammatical errors and are therefore correct as they appear in the sentence.

Q3. Select the option which fits appropriately in the blank:I am in London this Summer, I _ English.

• A. Learn
• B. Learns
• C. Am learning✓
• D. Learning

Explanation: This is the correct answer. "Am learning" is the present continuous tense of the verb "learn," used to describe actions that are happening now or around the present time. This sentence indicates that the speaker (I) is currently in the process of learning English while being in London.

Q4. Choose the correct sentence from the following options:

• A. The government should accrue taxes for strengthen the economy of the country.
• B. The government should accrue taxes in strengthen the economy of the country
• C. The government should accrue taxes to strengthen the economy of the country.✓
• D. The government should accrue taxes by strengthen the economy of the country.

Explanation: By comparing all four sentences ,you notice there is only one difference i.e. PREPOSITION and for fact the best suited is 'to strengthen'.

Q5. Use an appropriate article:We have _ small house in _ village in _ Netherlands.

• A. The, An, A
• B. An, A, The
• C. A, A, The✓
• D. A, An, The

Explanation: "We have a small house in a village in the Netherlands."Here's why each article is used:"A" before "small house": The indefinite article "a" is used before "small house" because it refers to one unspecified small house among possibly many."A" before "village": Similarly, "a" is used before "village" because it refers to one unspecified village among possibly many villages."The" before "Netherlands": The definite article "the" is used before "Netherlands" because it refers to a specific country, indicating that the house is located in the country known as the Netherlands.

Q6. Fill in the blank: I'm now going to give you 10 _ tips for running a really successful website.

• A. Invaluable✓
• B. Valueless
• C. Unworthy
• D. Unprofitable

Explanation: Invaluable is defined as something extremely useful; indispensable. Since these tips will help create a successful website, they are extremely helpful and thus important, making them invaluable.

Q7. Choose the correct option according to subject verb agreementMy friend _ (suffer) from cholera since August.

• A. Suffer
• B. Suffered
• C. Suffering
• D. Is suffering✓

Explanation: The correct form of verb that should be used here is: is suffering because Is suffering is the present continuous tense, which is used to describe an action that started in the past and is still continuing.

Q8. Use an appropriate article:I think _ man over there is very ill. He can't stand on his feet.

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

Explanation: "I think the man over there is very ill. He can't stand on his feet."Explanation of the article used:"the" before "man": The definite article "the" is used here because the speaker is referring to a specific man that both the speaker and the listener can identify or see. It indicates that there is only one man being talked about in the particular location indicated (over there).

Q9. None of them _ able to solve this question.

• A. is
• B. were✓
• C. will
• D. would

Explanation: "None" is often treated as plural when it refers to more than one person or thing, as in this case: "none of them"."Were" is the plural form of the verb "to be" used with plural subjects

Q10. Which one of the following is found in both messenger RNA and DNA of a mammalian cell?

• A. Double helical structure
• B. Ribose sugar
• C. Thymine
• D. Sugar - phosphate backbone✓

Explanation: As we can see that the double-helical structure and the nitrogenous base Thymine are exclusive to DNA, while RNA solely posses the Ribose sugar. However, the one thing common between the two genetic materials is the Sugar Phosphate Backbone. A sugar-phosphate backbone (alternating grey-dark grey) joins together the nucleotides in a DNA sequence. The sugar-phosphate backbone forms the structural framework of nucleic acids, including DNA and RNA. This backbone is composed of alternating sugar and phosphate groups and defines the directionality of the molecule.

Q11. The cells in our body are all genetically identical, apart from the:

• A. Somatic cells
• B. Reproductive cells✓
• C. Muscle fibers
• D. White blood cells

Explanation: Reproductive cells are different. They are produced in the gonads (ovaries in females and testes in males) and are specialized for the purpose of reproduction. In contrast to somatic cells, which have two copies of each chromosome (one from each parent), reproductive cells only have one copy of each chromosome. This is because they are produced through a process called meiosis, which involves two rounds of cell division. During meiosis, the homologous chromosomes (pairs of chromosomes that are identical in size and structure) are separated, resulting in cells with half the number of chromosomes as the original cell. This reduction in chromosome number is necessary for sexual reproduction, as it allows for the mixing of genetic material from two parents to create a new individual with a unique genetic makeup.

Q12. Transcription is the process in which an RNA copy of the DNA sequence and coding the gene is produced with the help of an enzyme called:

• A. DNA polymerase
• B. RNA polymerase✓
• C. DNA transcriptase
• D. RNA transcriptase

Explanation: RNA polymerase is the main transcription enzyme. RNA polymerase uses one of the DNA strands (the template strand) as a template to make a new, complementary RNA molecule. DNA polymerase is an enzyme that synthesizes DNA molecules from deoxyribonucleotides, which are the building blocks of DNA. The enzymes play an essential role in DNA replication, usually working in pairs to produce two matching DNA stranges from a single DNA molecule. There are no enzymes known as DNA or RNA transcriptase. However, we have Reverse Transcriptase (RT) which is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed as 'reverse transcription'.

Q13. In a typical menstrual cycle of 28 days, what is the most likely fertile period?

• A. Days 5 to 10
• B. Days 1 to 5
• C. Days 14 to 15✓
• D. Days 11 to 14

Explanation: In a typical menstrual cycle of 28 days, the most likely fertile period, when a woman is more likely to conceive, is around the middle of the cycle. Ovulation, the release of a mature egg from the ovary, typically occurs approximately 14 days before the start of the next menstrual period in a 28-day cycle. Ovulation usually occurs around day 14 in a 28-day cycle, but it can vary. This is the most fertile period, as the egg is released and can be fertilized by sperm.

Q14. Centrosome is found in:

• A. Cytoplasm✓
• B. Nucleus
• C. Chromosomes
• D. Nucleolus

Explanation: The centrosome is found in the cytoplasm of animal cells. The centrosome is a small organelle that plays a crucial role in cell division (mitosis) and is involved in organizing the microtubules of the cell's cytoskeleton. It consists of two centrioles, which are cylindrical structures composed of microtubules. The centrosome is located near the nucleus in the cytoplasm and serves as the main microtubule organizing center (MTOC) in animal cells.

Q15. Which of the following causes mad cow disease?

• A. Prion✓
• B. Virus
• C. Bacteria
• D. Both a and b

Explanation: Mad Cow Disease (Bovine Spongiform Encephalopathy, BSE) is a fatal neurodegenerative disorder in cattle caused by prions—misfolded proteins that damage the brain. It spreads mainly through contaminated feed containing infected nervous tissue. In cattle, symptoms include loss of coordination, behavioral changes, difficulty walking, weight loss, and death. In humans (variant Creutzfeldt–Jakob disease), it causes memory loss, confusion, personality changes, muscle stiffness, and coordination problems, eventually leading to coma and death. Prevention relies on banning contaminated animal feed, strict meat inspection, and culling infected animals.

Q16. Which type of evolution is represented by analogous organs?

• A. Divergent evolution
• B. Coevolution
• C. Parallel evolution
• D. Convergent evolution✓

Explanation: Analogous organs are a hallmark of convergent evolution. These organs arise when distantly related species independently develop similar traits to adapt to similar environmental pressures, despite not sharing a recent common ancestor. This is distinct from divergent evolution, which involves species with a common ancestor evolving differences due to varying selective pressures. Coevolution involves mutual evolutionary influences between interacting species, and parallel evolution involves similar traits developing in related species independently. Thus, convergent evolution best describes the development of analogous organs.

Q17. This theory says that “mitochondria and chloroplasts are, in effect, ancient bacteria which now live inside the larger cells”:

• A. Darwin’s theory of evolution
• B. Lamarckism
• C. Neo - darwinism
• D. Endosymbiont theory✓

Explanation: The endosymbiotic theory states that some of the organelles in today's eukaryotic cells were once prokaryotic microbes. They eventually lost their cell wall and much of their DNA because they were not of benefit within the host cell. Mitochondria and chloroplasts cannot grow outside their host cell. The illustration of the prokaryotic microbes penetrating into the now called eukaryotes is presented below:

Q18. The organs which are similar in function but different in structure, are called:

• A. Analogous organs✓
• B. Convergent evolution
• C. Homologous organs
• D. Divergent evolution

Explanation: Analogous organs, such as the wings of birds and bats, are adapted for flying but developed through different evolutionary paths, indicating that they do not share a common ancestor for this trait. In contrast, homologous organs, like the forelimbs of mammals, share a common structure due to shared ancestry but may serve different functions. Convergent evolution describes the process leading to analogous traits, while divergent evolution explains how species with a shared ancestor can develop different traits. Thus, the correct answer is 'Analogous organs' as they match the description of having similar functions but different structures.

Q19. The infection of lungs is called:

• A. Emphysema
• B. Asthma
• C. Pneumonia✓
• D. Bronchitis

Explanation: Pneumonia – An Infection that inflames the air sacs (alveoli) in the lungs, which may fill with fluid or pus.Causes: Bacteria, viruses, fungiSymptoms: Cough, fever, chest pain, difficulty breathing

Q20. Which type of bond is not responsible in maintaining the tertiary structure of proteins?

• A. Ionic bond
• B. Hydrogen bond
• C. Peptide bond
• D. Glycosidic✓

Explanation: The type of bond that is not responsible for maintaining the tertiary structure of proteins is the peptide bond. Peptide bonds are responsible for linking individual amino acids together to form the primary structure of a protein, which is simply the linear sequence of amino acids.The tertiary structure of a protein is the three-dimensional arrangement of the protein's polypeptide chain, resulting from interactions between amino acid residues that are not adjacent in the primary sequence. These interactions can be of various types, including:1. Hydrogen bonds: These weak bonds form between the hydrogen atom of one amino acid's side chain and another atom (oxygen or nitrogen) in the side chain of a different amino acid.2. Disulfide bonds: These covalent bonds are formed between the sulfur atoms of two cysteine residues in the protein, creating a bridge that stabilizes the protein's tertiary structure.3. Ionic bonds (salt bridges): These are electrostatic interactions between charged amino acid side chains (e.g., positively charged lysine and arginine with negatively charged aspartate and glutamate).4. Hydrophobic interactions: Nonpolar amino acid side chains tend to cluster together in the protein's interior to avoid water, stabilizing the tertiary structure.5. Van der Waals forces: These weak attractions occur between atoms that are in close proximity, helping to stabilize the protein's tertiary structure.The combination of these various interactions contributes to the overall folding and stability of the protein's tertiary structure, allowing it to perform its specific biological functions.

Q21. Each air-sac consists of several microscopic single layered structures called:

• A. Bronchioles
• B. Windpipe
• C. Bronchi
• D. Alveoli✓

Explanation: Alveoli are tiny air sacs in your lungs that take up the oxygen you breathe in and keep your body going. Although they're microscopic, alveoli are the workhorses of your respiratory system. People have an average of 480 million alveoli in their lungs, located at the end of bronchial tubes.

Q22. Which of the following are assembled and disassembled during the cell cycle?

• A. Microtubules✓
• B. Microfilaments
• C. A and B both
• D. None of these

Explanation: The cell cycle is the process by which a cell grows, duplicates its genetic material, and divides into two daughter cells. It consists of four main stages: G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis). During G1, the cell prepares for DNA replication. In the S phase, DNA synthesis occurs, resulting in two identical copies of the cell's DNA. G2 is a preparation phase before cell division. Finally, during the M phase, the cell divides into two daughter cells through either mitosis (for somatic cells) or meiosis (for reproductive cells).Microtubules are dynamic structures that are assembled and disassembled during the cell cycle. They are involved in a variety of cellular processes including chromosome segregation during mitosis and meiosis, intracellular transport of organelles and vesicles, and maintenance of cell shape and polarity. The assembly and disassembly of microtubules are tightly regulated by a variety of cellular factors and play critical roles in maintaining cellular homeostasis. Microfilaments and intermediate filaments are also part of the cytoskeleton, but they do not undergo dynamic assembly and disassembly during the cell cycle.

Q23. Skeletal muscle is composed of cells collectively referred to as:

• A. Muscle fibrin
• B. Muscle fibers✓
• C. Sarcomere
• D. None of these

Explanation: Skeletal muscle is composed of long, cylindrical cells called muscle fibers, which are multinucleated and contain many myofibrils. These myofibrils are composed of repeating units called sarcomeres, which are responsible for the muscle's contraction and movement. Characteristics of Skeletal MuscleVoluntary Control → Controlled by the nervous system (somatic nervous system)Striated → Has alternating light and dark bands due to actin and myosin filamentsMultinucleated → Each muscle fiber has multiple nucleiFatigue-Prone → Can get tired after prolonged activity

Q24. The uterus of the female reproductive system opens into the:

• A. Placenta
• B. Birth canal✓
• C. Cervix
• D. All of these options are correct

Explanation: The uterus of the female reproductive system opens into the vagina. The birth canal is the other name for the vagina. The cervix, which is the lower part of the uterus, protrudes into the upper part of the vagina. During childbirth, the cervix dilates to allow the passage of the baby from the uterus into the vagina and eventually out of the body. The vagina serves as a muscular tube that connects the uterus to the external body surface and functions in sexual intercourse, as well as the passage for menstrual flow and childbirth.

Q25. Composite of an organism's observable characters or traits is called?

• A. Genotype
• B. Phenotype✓
• C. Recombinant
• D. Replication

Explanation: A phenotype is an individual's observable traits, such as height, eye color, and blood type. The genetic contribution to the phenotype is called the genotype.

Q26. _ occurs because natural selection gives some alleles a better chance of survival than others:

• A. Fitness
• B. Evolution✓
• C. Crossing over
• D. Artificial Selection

Explanation: A mechanism of evolution in which allele frequencies of a population change over generations due to chance.Some chances favor more to a specific allele as compared to its counterparts,thus remains.Some variations make an individual better suited to survive and reproduce in their environment. Natural selection is a mechanism, or cause, of evolution.

Q27. What is the effect of enzyme DNA ligase?

• A. DNA is broken up at specific sites
• B. DNA fragments are joined together✓
• C. DNA replication occurs
• D. DNA transcription occurs

Explanation: DNA ligases play an essential role in maintaining genomic integrity by joining breaks in the phosphodiester backbone of DNA that occur during replication and recombination, and as a consequence of DNA damage and its repair. DNA ligase sticks the DNA nucleotide backbone by forming phosphodiester linkages between two successive nucleotides as shown in the diagram below:

Q28. The end product in anaerobic respiration is:

• A. Ethanol and Carbon dioxide
• B. Lactate
• C. Pyruvate
• D. Both A and B✓

Explanation: The end products of anaerobic respiration depend on the specific type of anaerobic process involved. There are two main types of anaerobic respiration: lactic acid fermentation and alcoholic fermentation. In lactic acid fermentation, the end product is lactic acid.This process occurs in various microorganisms and in muscle cells during strenuous exercise when oxygen is not available in sufficient amounts to support aerobic respiration. The overall reaction is:Glucose → 2 Lactic Acid + Energy (in the form of ATP) In alcoholic fermentation, the end products are ethanol and carbon dioxide. This process is commonly carried out by yeast and some bacteria in the absence of oxygen.The overall reaction is:Glucose → 2 Ethanol + 2 Carbon Dioxide + Energy (in the form of ATP).

Q29. The semi-solid mass in stomach is known as:

• A. Bolus
• B. Chyme✓
• C. Serum
• D. Food

Explanation: 'Chyme' or chymus is the semi-fluid mass of partly digested food that is expelled by a person's stomach, through the pyloric valve, into the duodenum. Chyme results from the mechanical and chemical breakdown of a bolus and consists of partially digested food, water, hydrochloric acid, and various digestive enzymes.

Q30. In Morgan's linkage experiment, when males and females of the F2 generation mate with each other and produce offspring, the percentage of recombinants was:

• A. 37✓
• B. 22
• C. 2
• D. 70

Explanation: Morgan and his students have found that linked genes show varied recom­binations, some being more tightly linked than others. (i) In Drosophila, a crossing of yellow-bodied (Y) and white-eyed (W) females with brown-bodied (Y+) red-eyed (W+) males produced F1 to be brown-bodied red-eyed. On intercrossing of F1 progeny, Morgan observed that the two genes did not segregate independently of each other and, therefore, the F2 ratio deviated significantly from the expected 9: 3: 3: 1 ratio. He found 98.7% to be parental and only 1.3% recombinants. (ii) In a second cross in Drosophila between white-eyed and miniature-winged (mm) females with wild type or red-eyed normal winged (w+w+m+m+) males, all the F1 were found to be of wild type, i.e., red-eyed and normal winged. An F1 female fly was then test crossed with white-eyed and miniature winged male. 62.8% of the progeny was of parental types while 37.2% were recombinants.

Q31. The human embryo remains enclosed in:

• A. Amniotic sac✓
• B. Placenta
• C. Chorion
• D. Allantois

Explanation: The human embryo remains enclosed in the amniotic sac, a fluid-filled membrane that provides protection and a stable environment for development. The sac is filled with amniotic fluid, which cushions the embryo against mechanical shocks, prevents dehydration, and allows free movement essential for proper growth. The amniotic sac, along with the placenta and umbilical cord, plays a crucial role in supporting the embryo throughout pregnancy by facilitating nutrient exchange and waste removal while safeguarding it from external harm.

Q32. Which of the following organs serves no apparent purpose?

• A. Non-vestigial organs
• B. Homologous organs
• C. Analogous organs
• D. Vestigial organs✓

Explanation: Option D is correct because vestigial organs are structures that were once useful in an organism's ancestors but have since become reduced or obsolete, serving no significant purpose in the current form of the organism. Examples include the human appendix and the pelvic bones in whales.Options A, B, and C are incorrect because non-vestigial organs, homologous organs, and analogous organs all serve specific, important functions in the organisms possessing them. Non-vestigial organs are essential for survival, homologous organs indicate a common ancestry but may have adapted to different uses, and analogous organs perform similar functions but arise from different evolutionary pathways.

Q33. In humans only one ovum is usually discharged from the ovary at one time this phenomenon is called?

• A. Ovulation✓
• B. Menstruation
• C. Oestrous
• D. All of these

Explanation: Ovulation is the phenomenon in which one mature egg (ovum) is released from the ovary into the fallopian tube. It is a crucial event in the menstrual cycle and occurs approximately halfway through the cycle.

Q34. Haemoglobin synthesis takes place in all except _.

• A. Reticulocytes
• B. Erythrocyte✓
• C. Basiophilic erythroblasts
• D. None of these

Explanation: Option A: Reticulocytes are immature red blood cells that still contain remnants of ribosomes and RNA. They are produced in the bone marrow and go through a process of maturation before becoming fully functional erythrocytes. During their maturation, reticulocytes synthesize haemoglobin, the protein responsible for carrying oxygen in the blood.Option B: Erythrocytes, also known as red blood cells, are the mature form of red blood cells. They have a distinct biconcave shape and lack a nucleus and most organelles. Mature erythrocytes are specialized for oxygen transport and do not have the ability to synthesize new proteins, including haemoglobin. Their primary function is to circulate in the bloodstream and transport oxygen from the lungs to the body tissues.Option C: Basophilic erythroblasts are nucleated precursor cells of red blood cells found in the bone marrow. They undergo a series of maturation steps to develop into reticulocytes, which eventually become mature erythrocytes. During their maturation, basophilic erythroblasts actively synthesize haemoglobin to support the oxygen-carrying capacity of the developing red blood cells.

Q35. The enzyme-substrate complex is formed in which part of the enzyme molecule?

• A. Active site✓
• B. Allosteric site
• C. Catalytic site
• D. None of the above

Explanation: The correct answer is the active site, which is the specific region of the enzyme where the substrate binds, forming the enzyme-substrate complex. This interaction is crucial for catalysis as it aligns the substrate for the chemical reaction. The allosteric site affects enzyme activity through regulation but does not participate in the initial substrate binding. The catalytic site is often considered part of the active site, focusing on the chemical transformation aspect rather than the initial binding.

Q36. The total aggregate of genes in a population at any one time is called population's?

• A. Genome
• B. Gene pool✓
• C. Genetic group
• D. Genomic library

Explanation: Explanation: A gene pool is the total set of genes and their alleles that exist in a population at any given time. It represents the genetic diversity of the population and is affected by various factors such as mutation, migration, genetic drift, and natural selection. The term "genome" refers to the entire set of an organism's DNA, while "genomic library" refers to a collection of cloned DNA fragments that represent the entire genome of an organism. "Genetic group" is not a commonly used term in population genetics.

Q37. Reverse transcriptase is a useful enzyme to have when:

• A. RNA virus converts its RNA to DNA✓
• B. There are no host cells present
• C. Nutrients are scarce
• D. Spikes are forming in the new virus

Explanation: Reverse transcriptase is an enzyme that allows the conversion of RNA into DNA. It is commonly found in retroviruses, such as HIV, where it plays a crucial role in the replication of the viral genome. By converting the viral RNA into DNA, the virus is able to integrate its genetic material into the host cell's DNA and hijack the host's cellular machinery to produce new virus particles. Reverse transcriptase is also used in molecular biology research, such as in the polymerase chain reaction (PCR) technique.

Q38. Which of the following is not related to enveloped viruses?

• A. They survive for a short time.
• B. They are tolerant to antibodies.✓
• C. Their envelope is sensitive to sunlight.
• D. Envelope is derived from host..

Explanation: Enveloped viruses are less resistant to antibodies or disinfectants and can be easily destroyed. The envelope is derived from the host and is sensitive to sunlight. They survive for a short time.

Q39. Numerous opportunistic diseases can affect individuals with the following conditions.

• A. Measles
• B. Influenza
• C. Hepatitis A
• D. AIDS✓

Explanation: Among the given options, the correct answer is d. AIDS. Measles, influenza, and hepatitis A can temporarily weaken the immune system, increasing susceptibility to other infections, but they are not classified as opportunistic infections. In contrast, AIDS (Acquired Immunodeficiency Syndrome), caused by HIV, leads to a profound loss of CD4⁺ T cells and severe immunodeficiency. This immunosuppressed state is specifically characterized by the occurrence of opportunistic infections such as tuberculosis, pneumonia, candidiasis, and other fungal, bacterial, and viral diseases. Thus, unlike measles, influenza, and hepatitis A, AIDS is directly associated with opportunistic infections due to its defining immune system damage.

Q40. The complete, mature, and infectious virus particle is known as:

• A. Capsomere
• B. Genome
• C. Virion✓
• D. Capsid

Explanation: The correct answer is c. Virion. A virion is the complete, mature, and infectious virus particle, consisting of the viral genome (DNA or RNA) enclosed within a protective protein coat called the capsid. Unlike the genome or capsid alone, which are only parts of a virus, the virion represents the fully assembled unit capable of infecting host cells.

Q41. Cholesterol is:

• A. Animal sterol
• B. C27H46O
• C. Have 5 methyl groups
• D. All of these✓

Explanation: Cholestrol is an animal sterol which the structure shown below indicating the presence of 5 methyl groups and the molecular formula C27H46O.

Q42. Which type of bonds are never formed when a substrate fits into the active site of an enzyme?

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

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

Q43. Enzymes which are involved in transfer of electrons are known as?

• A. Oxidases
• B. Dehydrogenases
• C. Hydrolyses
• D. Both a and b✓

Explanation: Oxidases are enzymes that catalyze the transfer of electrons from a substrate to oxygen, while dehydrogenases are enzymes that catalyze the transfer of electrons from a substrate to an electron acceptor (such as NAD+ or FAD). Both of these types of enzymes are involved in the transfer of electrons, which is a key aspect of many metabolic pathways.

Q44. The specificity of an enzyme is due which of the following?

• A. Protein nature
• B. Active site✓
• C. Globular shape
• D. Co-factor

Explanation: The specificity of an enzyme is primarily due to the unique structure of its active site. The active site is a specific region on the enzyme's three-dimensional structure where the substrate (the molecule upon which the enzyme acts) binds during a catalytic reaction. The specificity arises from both the shape and the chemical properties of the active site.

Q45. Doctors use a stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when:

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

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

Q46. Erythropoiesis starts in:

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

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

Q47. The smallest contractile unit of muscle contraction, called a sarcomere, is the area between two?

• A. H zone
• B. M line
• C. Z line✓
• D. Z zone

Explanation: The correct answer is the Z line. The sarcomere is the basic contractile unit of muscle fibers and is defined by the area between two Z lines. These lines serve as anchor points for actin filaments and help maintain the structure during contraction. The H zone and M line are internal components of the sarcomere that do not define its boundaries. The term 'Z zone' is not used in muscle anatomy; thus, it is not a correct option.

Q48. Which of the following is not true about the human immunodeficiency virus?

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

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

Q49. Primordial soup is a set of hypothetical conditions on ancient Earth first proposed by?

• A. Dmitri Ivanovsky
• B. Dmitry Anuchin
• C. Nikolay Shatsky
• D. Alexander Oparin✓

Explanation: Alexander Oparin is credited with the primordial soup hypothesis, suggesting that life on Earth originated from a series of chemical reactions in a nutrient-rich 'soup' of organic compounds. This idea was groundbreaking in understanding abiogenesis. The other individuals listed — Dmitri Ivanovsky, Dmitry Anuchin, and Nikolay Shatsky — were influential in their respective fields of virology, anthropology, and geology, but did not propose theories on the origin of life or the primordial soup.

Q50. What is the most important structure between body and brain?

• A. Neck
• B. Spinal cord✓
• C. Blood vessels
• D. Skeleton

Explanation: The spinal cord is the centre for many reflexes, and it serves as a pathway for the conduction of impulses to and from different parts of the body and brain. Messages from the body and the brain run up and down the spinal cord, the body's information highway.

Q51. Which of the following is the respiratory surface in human beings?

• A. Lungs
• B. Alveoli✓
• C. Windpipe
• D. Alveolar duct

Explanation: The respiratory surface is the actual surface where the exchange of gases actually takes place. In humans, the respiratory surface is the alveoli. Hence, option B is the correct option.

Q52. The offspring of mating between two pure stains are called:

• A. Hybrid✓
• B. The P generation
• C. Mutants
• D. The F2 generation

Explanation: When two individuals of different pure breeding strains or genotypes are crossed, their offspring are known as hybrids. The offspring of the first generation (F1 generation) resulting from the cross between two parental strains are all hybrids, which have a mixed genetic makeup from both parents.

Q53. Which of the following is the name of the modified endoplasmic reticulum found in muscle cells?

• A. T-tubule
• B. Sarcomere
• C. Myoplasmic reticulum
• D. Sarcoplasmic reticulum✓

Explanation: The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the smooth endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions (Ca2+).

Q54. Carbohydrate catabolism is concerned with the fate of:

• A. ATP
• B. Amino acid
• C. Glucose✓
• D. All of these

Explanation: Glucose is a simple sugar, a monosaccharide, and is a primary source of energy for cells. Glucose is broken down through cellular respiration to produce adenosine triphosphate (ATP), the energy currency of cells.Glucose is broken down through cellular respiration to produce adenosine triphosphate (ATP), the energy currency of cells.

Q55. The scrotum is responsible for·which of the following in the male reproductive system?

• A. Synthesis of sperm
• B. Lubrication
• C. Nourishment of sperm
• D. Temperature regulation✓

Explanation: The 'temperature' is controlled by the scrotal movement of the testes away or toward the body depending on the environmental temperatures. Moving the testes away from the abdomen and increasing the exposed surface area allows a faster dispersion of excess heat.

Q56. This carries the egg to the uterus:

• A. Fallopian tube✓
• B. Ovary
• C. Cervix
• D. Vagina

Explanation: The structure that carries the egg from the ovary to the uterus is the fallopian tube, also known as the oviduct. After ovulation, the released egg travels through the fallopian tube, where it may encounter sperm for fertilization. If fertilization occurs, the resulting zygote will continue to develop as it moves down the fallopian tube toward the uterus, where it eventually implants into the uterine lining. If fertilization does not occur, the egg will not be fertilized and will be expelled from the body during menstruation.

Q57. Thymus, spleen, tonsils and adenoids produce:

• A. Erythrocytes
• B. Lymphocytes✓
• C. Phagocytes
• D. Thrombocytes

Explanation: The thymus, spleen, tonsils, and adenoids produce lymphocytes. The thymus is the primary lymphoid organ where T cells (a type of lymphocyte) mature. The spleen is the secondary lymphoid organ where B cells (another type of lymphocyte) mature and produce antibodies. The tonsils and adenoids are also secondary lymphoid organs that help trap and fight infection.

Q58. The furan ring is an important structural component of biological molecules. How many carbon atoms are required to form ribofuranose?

• A. 3
• B. 5✓
• C. 6
• D. 2

Explanation: Ribofuranose is a type of sugar molecule that contains a furan ring structure. The furan ring is a five-membered ring that contains four carbon atoms and one oxygen atom. Therefore, five carbon atoms are required to form ribofuranose.

Q59. Biorhythms are called circadian which means about one day so they are also called?

• A. Diurnal tempo
• B. Diurnal time
• C. Diurnal rhythms✓
• D. All of these

Explanation: "Diurnal rhythms" are the circadian rhythm synced with day and night (24 hours). Biorhythms are often referred to as "diurnal rhythms" because they are biological cycles that repeat approximately every 24 hours, corresponding to the day-night cycle. Option A,B and D are incorrect.

Q60. Two populations of the same species over time grow distant from one another. At what point will these two populations be considered different species?

• A. When the populations begin to eat different foods
• B. When there is a physical barrier, such as a river, between the two populations
• C. When the two populations have not been in contact with one another for two hundred years
• D. When they are no longer able to interbreed✓

Explanation: Speciation is defined by the biological concept of species, which states that species are groups of interbreeding natural populations that are reproductively isolated from other such groups. Therefore, two populations become distinct species when they can no longer interbreed, not merely because of different diets, physical separations, or long periods of isolation. The correct option (D) highlights the importance of reproductive isolation, which is a key element in the process of speciation. Other options fail to address this crucial factor and are therefore incorrect.

Q61. What are osteocytes?

• A. White blood cells
• B. Bone cell✓
• C. Brain cell
• D. None of these

Explanation: Option A: White blood cells: Cells involved in the immune system’s defense against infections and foreign substances. Option B: Osteocytes are a type of bone cell that are embedded within the bone tissue. They are the most abundant and mature cells in the bone. They are involved in regulating bone remodeling, mineral homeostasis, and detecting mechanical stress on the bone. Option C: Brain cell: Neurons, or brain cells, transmit signals and facilitate communication in the nervous system.

Q62. The lipid vesicles used for drug delivery system called:

• A. Inositides
• B. Lipoproteins
• C. Liposomes✓
• D. Drugoles

Explanation: Liposomes are lipid vesicles that are used as a drug delivery system. They are made up of a phospholipid bilayer and can encapsulate both hydrophilic and hydrophobic drugs. They have gained significant attention in drug delivery systems due to their biocompatibility, biodegradability, and low toxicity. Liposomes can also be modified to target specific tissues or cells, which makes them an attractive option for targeted drug delivery.

Q63. The enzyme that seals the foreign piece of DNA into the vector is called:

• A. DNA polymerase
• B. DNA helicase
• C. DNA ligase✓
• D. DNA primase

Explanation: DNA ligase is the anzyme that joins DNA fragments by forming phosphodiester bonds, effectively sealing a foreign piece of DNA into a vector.

Q64. A mutant strain of T4 ­- Bacteriophage, R­-II, fails to lyse the E. coli but when two strains R­-IIX and R-­IIY are mixed then they lyse the E. coli. What may be the possible reason?

• A. Bacteriophage transforms in wild.
• B. It is not mutated.
• C. Both strains have similar cistrons.
• D. Both strains have different cistrons.✓

Explanation: A mutant strain of T4 - bacteriophage, RII, fails to lyse the E.coli but when two strains R-­II (X) and R-­IIY are mixed then they lyse the E.coli because both strains have different cistrons.

Q65. In Lederberg’s replica plating experiment what shall be used to obtain streptomycin resistant strain?

• A. Minimal medium and Streptomycin✓
• B. Complete medium and Streptomycin
• C. Only minimal medium
• D. Only complete medium.

Explanation: If Streptomycin resistant mutant is to be obtained, the material should be allowed to grow on medium lacking streptomycin so that both mutant and wild types may grow. These colonies are imprinted on Petri plates to form the master pattern and other plates having streptomycin can then be pressed on velveteen to get an impression. The plate now containing only mutants for Streptomycin resistance will grow.

Q66. Among the following edible fishes, which one is a marine fish having a rich source of omega­-3 fatty acids?

• A. Mystus
• B. Mangur
• C. Mrigala
• D. Mackerel✓

Explanation: Mackerel is a marine fish, rich in omega­-3­ fatty acids. Mystus, Mangur and Mrigala are freshwater fishes.

Q67. Interspecific hybridization is the mating of:

• A. Animals within same breed without having common ancestors
• B. Two different related species✓
• C. Superior males and females of different breeds.
• D. More closely related individuals within same breed for 4-6 generations.

Explanation: In interspecific hybridization, a species is mated with a different related species of the same genus. Interspecific hybrids are generally difficult to produce, but they are important in plant breeding, particularly in breeding for disease resistance. This is also called intrageneric hybridization.

Q68. Haploids are more suitable for mutation studies than the diploids. This is because

• A. Haploids are more abundant in nature than diploids
• B. All mutations, whether dominant or recessive are expressed in haploids✓
• C. Haploids are reproductively more stable than diploids
• D. Mutagens penetrate in haploids more effectively than in diploids.

Explanation: Haploid plants, are always pure because they possess only one set of chromosomes. So, the mutations are expressed very easily in haploid plants as compared to diploid plants.

Q69. Somaclones are obtained by :

• A. Plant breeding
• B. Irradiation
• C. genetic Engineering
• D. Tissue culture.✓

Explanation: Genetic variation present among plant cells during tissue culture is called somaclonal variation. The term somaclonal variation is also used for the genetic variation present in plants regenerated from a single culture. This variation has been used to develop several useful varieties.

Q70. Before carrying out PCR:

• A. Gene product must be available
• B. Vector must be available
• C. Primers must be available✓
• D. Bacteriophage must be available

Explanation: As DNA polymerase cannot initiate a polynucleotide chain, rather it can elongate a polynucleotide chain.

Q71. To clean up environmental pollutants, increase the fertility of the soil and kill insect pests, genetically engineered:

• A. Animals have been used
• B. Bacteria have been used✓
• C. Plants have been used
• D. Viruses have been used

Explanation: Genetically engineerad bacteria are used to remove environmental pollutants through bioremediation. Thay also help increase soil fertility and can be modified to control insect pests.

Q72. A technique used for correcting defective genes responsible for disease development:

• A. Gene therapy✓
• B. Cloning
• C. Tissue culture
• D. Gene sequencing

Explanation: Gene therapy is a technique that uses a gene(s) to treat, prevent or cure a disease or medical disorder.

Q73. Animals cope with the temperature extremes through a homeostatic mechanism called:

• A. Evaporative Cooling
• B. Shivering Thermogenesis
• C. Non-shivering Thermogenesis
• D. Thermoregulation✓

Explanation: The process mentioned in 'A', 'B' and 'C' are partially supportive in temperature maintenance, however thermoregulation is the homeostatic process used in this regard.

Q74. Each organism of a species has assumed, in evolutionary history a specific set up of _ at various levels of organization suitable to its surroundings.

• A. Internal environment✓
• B. External environment
• C. Intracellular environment
• D. Intercellular environment

Explanation: Internal environment refers to the conditions, variables, and factors within an organism's body that are crucial for maintaining its health and proper functioning. This concept is closely related to the idea of homeostasis, which is the body's ability to maintain a stable and balanced internal environment despite external changes. The internal environment encompasses a wide range of physiological and biochemical parameters, including temperature, pH, blood pressure, nutrient levels, waste product concentrations, and more.

Q75. The weight of kidneys accounts for less than_% of the total body weight:

• A. 10
• B. 20
• C. 1✓
• D. 0.1

Explanation: Kidneys contribute less than 1% of the total body weight, but they receive 20% of the total blood of the body with each cardiac beat. This indicates their physiological importance.

Q76. Kidneys receive _% of blood supplied with each cardiac beat:

• A. 1
• B. 10
• C. 5
• D. 20✓

Explanation: Kidney contributes less than 1% of the total body weight, but they receive 20% of the total blood of the body with each cardiac beat. This indicates their physiological importance.

Q77. Nephrons, in human kidneys, are arranged along two distinct regions, i.e.:

• A. An inner cortex and outer medulla
• B. An outer cortex and an inner medulla✓
• C. An inner cortex and an inner medulla
• D. An outer cortex and a middle medulla

Explanation: The kidney is organized into two main regions: the outer renal cortex and the inner renal medulla. The cortex contains the majority of the nephrons, which are essential for filtering blood and producing urine. The medulla, located deeper within the kidney, is involved in the concentration of urine. The other options incorrectly describe the anatomical layout by mislabeling the layers, which could lead to confusion in understanding kidney structure.

Q78. The structure that is specifically instrumental in the production of concentrated urine is:

• A. Cortical Nephron
• B. Juxtamedullary Nephron✓
• C. Counter Current Multiplier
• D. Restricted Supply of Water

Explanation: Juxtamedullary nephrons have distinct features and functions that make them well-suited for the production of concentrated urine. Juxtamedullary nephrons are primarily located in the inner part of the renal cortex and extend deep into the renal medulla. This positioning allows them to play a key role in regulating water balance and the concentration of urine. Juxtamedullary nephrons make up a smaller portion of the total nephrons in the kidney, but they play a critical role in maintaining water balance and regulating the concentration of urine. The combination of long loops of Henle and the countercurrent mechanism allows the kidney to conserve water when necessary, which is particularly important in maintaining overall body homeostasis, especially in situations of dehydration.

Q79. The nephrons arranged along the cortex are called:

• A. Cortical✓
• B. Juxtamedullary
• C. Juxtacortical nephron
• D. Medullary

Explanation: Nephrons that are arranged along the cortex of the kidney are called "cortical nephrons." Cortical nephrons are one of the two main types of nephrons found in the human kidney, with the other type being juxtamedullary nephrons. These two types of nephrons have distinct features and functions within the kidney. Cortical nephrons are primarily located in the outer part of the renal cortex, and they do not extend deeply into the renal medulla. They play essential roles in the initial filtration of blood, reabsorption of nutrients and electrolytes, and regulation of overall body homeostasis. Unlike juxtamedullary nephrons, cortical nephrons do not have long loops of Henle that extend deeply into the renal medulla, and they do not play a primary role in the concentration of urine.

Q80. It is the kidney machine that works on the same principle as the kidney for removal of wastes and excess water from the blood:

• A. Catheter
• B. Peritoneum
• C. Dialyzer✓
• D. Epithelium

Explanation: A dialyzer, also known as a hemodialyzer or artificial kidney, is a medical device used in hemodialysis, a life-sustaining procedure that removes waste products, excess fluids, and electrolytes from the blood in individuals with kidney failure or end-stage renal disease (ESRD). The dialyzer is a crucial component of a hemodialysis machine and serves as an artificial filter for cleansing the patient's blood during hemodialysis treatments.The dialyzer is a critical component of the hemodialysis process, as it effectively cleanses the patient's blood, removing waste products and excess fluids to help maintain their overall well-being.

Q81. What is correct about myoglobin?

• A. It is an iron-containing protein pigment
• B. It is found in muscle fibers
• C. It stores oxygen
• D. All of these✓

Explanation: Myoglobin is indeed an iron-containing protein pigment, which is what gives muscle tissues their reddish color. It is found in muscle fibers, where it plays a vital role in storing oxygen. This oxygen storage is crucial for muscle function, as it allows for sustained energy production during muscle contraction. Each of the individual options describes a true characteristic of myoglobin, making 'All of these' the correct choice.

Q82. Homeostasis is the _

• A. Tendency to change with environmental changes
• B. Tendency to resist change and maintain stability✓
• C. Disturbance in regulatory control
• D. Use of plants and animal extracts in homeopathy

Explanation: Homoeostasis is the regulation, by an organism, of the chemical composition of its body fluids and other aspects of its internal environment so that physiological processes can proceed at optimum rates. It involves monitoring changes in the external and internal environment by means of receptors and adjusting the composition of the body fluids accordingly; excretion and osmoregulation are important in this process. Example of homeostatic regulation are the maintenance of the acid-base balance and body temperature.

Q83. Which one of the following characteristics is common both in humans and adult frogs?

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

Explanation: Excretion of urea is known as ureotelism and the animals which excrete urea are called ureotelic. Ureotelic animals include Ascaris, earthworm (both are ammonotelic and ureotelic), cartilaginous fishes like sharks and sting rays, semiaquatic amphibians such as frogs and toads, aquatic or semiaquatic reptiles like turtles, terrapins and alligators, and man and all other mammals. Urea is less toxic and less soluble in water than ammonia. Hence, it can stay for some time in the body. Amphibian tadpole (e.g., tadpole of frog) excrete ammonia but after metamorphosis frog excretes urea.

Q84. The DNA fragments separated on an agarose gel can be visualized after staining with:

• A. Acetocarmin
• B. Aniline blue
• C. Ethidium bromide✓
• D. Bromophenol blue

Explanation: DNA fragments are separated through gel electrophoresis. To visualize them, staining is required. Ethidium bromide (EtBr) is commonly used for this purpose. The stained DNA fragments are then exposed to UV radiation. This causes the fragments to emit a bright orange fluorescence. The resulting bands are visible under UV light.

Q85. What criterion is for DNA fragment movement on agarose gel during gel electrophoresis?

• A. The smaller the fragment size, the farther it moves✓
• B. Positively charged fragments move to farther end
• C. Negatively charged fragments do not move
• D. The larger the fragment size, the farther it moves

Explanation: Electrophoresis is a technique used for the separation of substances of different ionic properties. Since the DNA fragments are negatively charged molecules, they can be separated by allowing them to move towards the anode. DNA fragments move towards the anode according to their molecule's size through the pores of agarose gel. Thus, the smaller fragments move farther away as compared to larger fragments.

Q86. The main objective of the production/use of herbicide-resistant GM crops is to:

• A. Encourage eco­friendly herbicides
• B. Reduce herbicide accumulation in food articles for health safety✓
• C. Eliminate weeds from the field without the use of manual labour
• D. Eliminate weeds from the field without the use of herbicides.

Explanation: Genetic engineering has helped to develop such transgenic crop plants which are resistant to herbicides so that they are not damaged when farmers spray herbicides in the fields. Herbicide resistant plants have been developed in such a way that they continue to produce normal crop yield and at the same time remain unaffected by the activity of herbicides. These plants also reduces the use of weeding labour, farmer’s cost and increases yield.

Q87. Golden rice is a genetically modified crop plant where the incorporated gene is meant for the biosynthesis of:

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

Explanation: Golden rice is a transgenic variety of rice (Oryza sativa) engineered to produce beta-carotene, a precursor to vitamin A. The grains appear yellow due to the presence of beta-carotene, hence the name 'golden rice.' This genetic modification is intended to combat vitamin A deficiency, which is prevalent in regions relying heavily on rice as a staple food. Options A, C, and D are incorrect because golden rice is not designed to address deficiencies in Omega-3, Vitamin B, or Vitamin C.

Q88. Which kind of therapy was given in 1990 to a four­ year­ girl with Adenosine Deaminase (ADA) enzyme deficiency?

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

Explanation: Gene therapy is a technique of genetic engineering which involves the replacement of a faulty/disease-causing gene by a normal healthy functional gene. The first clinical ex-vivo gene therapy was given in 1990 to a 4­-year old girl with adenosine deaminase (ADA) enzyme deficiency. This enzyme is very important for the immune system to function and the deficiency of this enzyme can lead to severe combined immune deficiency (SCID).

Q89. Globular blood proteins that are produced by B-lymphocytes and that bind specifically to foreign antigenic materials in the body and destroy them:

• A. Viroid
• B. Immunity
• C. Antigen
• D. Antibody✓

Explanation: Globular blood proteins that are produced by B-lymphocytes and that bind specifically to foreign antigenic materials in the body and destroy them is called antibody.

Q90. Which one of the following statements is correct with respect to kidney function regulation?

• A. When someone drinks a large amount of water, ADH release is suppressed.✓
• B. Exposure to cold temperatures stimulates ADH release.
• C. An increase in glomerular blood flow stimulates formation of angiotensin II.
• D. During summer when the body loses a lot of water due to evaporation, the release of ADH is suppressed.

Explanation: Antidiuretic hormone (ADH) or vasopressin increases the reabsorption of water in the distal convoluted tubule, collecting tubules and collecting ducts of the nephrons of the kidneys. As a result, the reabsorption of water from the glomerular filtrate is increased. When someone drinks lot of water, requirement of absorption of water decreases, so ADH release is suppressed.

Q91. The alloy Duralumin is composed of _ of Al.

• A. 95%✓
• B. 90%
• C. 85%
• D. 80%

Explanation: Classical Duralumin contains about 95% aluminum, with the rast mainly copper, magnesium, and manganese. The small percentage of alloying metals makes it strong yet lightweight. It is widely used in aircraft and structural applications due to its high strength-to-weight ratio.

Q92. Which of the following values of heat of formation indicates that the product is least stable?

• A. - 94 kcal
• B. + 21.4 kcal
• C. - 231 kcal
• D. + 64.8 kcal✓

Explanation: In the context of heat of formation (ΔH), a negative value indicates that the formation of the compound is exothermic, meaning the compound is more stable compared to its constituent elements in their standard states.So, the least stable compound among the options provided would have the most positive (ΔH) value and option d has the most positive value ,hence that is the correct option.

Q93. The nature of binding force in ionic crystals is:

• A. Magnetic
• B. Repulsive
• C. Electrostatic✓
• D. Weak

Explanation: An ionic crystal consists of ions bound together by electrostatic attraction. The arrangement of ions in a regular, geometric structure is called a crystal lattice. Examples of such crystals are the alkali halides, which include: potassium fluoride (KF).

Q94. The atomic number is usually equal to _

• A. Electrons
• B. Protons✓
• C. Neutrons
• D. Positrons

Explanation: Atomic number equals the number of protons in the nucleus of an atom.

Q95. Which enthalpy change is relevant in the following process:Na(s) -> Na (g) ΔH = +107

• A. Enthalpy of atomization✓
• B. Enthalpy of fusion
• C. Enthalpy of vaporization
• D. Enthalpy of formation

Explanation: Option A, enthalpy of atomization, is the energy required to completely separate all the atoms in a chemical substance. The separated atoms are in a gaseous state and get separated from the corresponding substance in its standard state. Sodium is solid in its standard state, and after atomization, the atoms are in their gaseous state. Hence, this is the correct answer.Option B is the enthalpy change when a solid substance melts into a liquid. Here, the state change is from a solid to a gas, no liquid state involved.Option C is the enthalpy change when a liquid is vaporized into a gas. Here, a solid is atomized to its gaseous state so, vaporization does not apply here.Option D is the enthalpy change when one mole of a substance is formed from its constituent elements. This does not describe the given reaction.

Q96. In the electrolysis of NaNO3(aq), Na+ is:

• A. Discharged at anode
• B. Discharge at cathode
• C. Do not discharge✓
• D. None of these options is correct

Explanation: At Cathode Sodium is not discharged but H2 gas is discharged. Sodium remains in the solution and more H2 gas is formed at the end of electrolysis.

Q97. One mole of substance at STP has:

• A. 2.24 dm³
• B. 24.4 dm³
• C. 2.44 dm³
• D. 22.4 dm³✓

Explanation: Under Standard Temperature and Pressure (STP), one mole of an ideal gas occupies 22.4 dm3.Under room conditions/ Normal Temperature and Pressure (NTP), one mole of an ideal gas occupies 24 dm3.

Q98. H2S is an example of _ hydride.

• A. Ionic
• B. Covalent✓
• C. Complex
• D. Metallic
• E. Border-line hydride

Explanation: Covalent hydrides are formed when hydrogen reacts with other similar electronegative elements like Si, C,etc. H2S is a covalent hydride because the two elements used in the formation of this hydride are non-metals.

Q99. sp3 hybridization in CH4 gives it _ geometry.

• A. Linear
• B. Coplanar
• C. Tetrahedral✓
• D. Octahedral
• E. Trigonal pyramid

Explanation: The correct answer is Tetrahedral. In CH4, the carbon atom undergoes sp3 hybridization, forming four equivalent hybrid orbitals that orient in a way to minimize electron pair repulsion, resulting in a tetrahedral geometry. This arrangement allows for the formation of four equivalent C-H bonds with bond angles of approximately 109.5°.Other options are incorrect because:Linear: Associated with sp hybridization, not applicable to CH4.Coplanar: Linked to sp2 hybridization, not CH4.Octahedral: Requires six bonding sites, unlike CH4.Trigonal pyramid: Involves a lone pair, which CH4 does not have.

Q100. The transparent plastic used to make combs and hairbrushes is called:

• A. PVA
• B. PVC
• C. Bakelite
• D. Perspex✓

Explanation: Perspex is a hard, brittle, and clear polymer that is mostly used in packaging materials, bowls, toys, combs, trays, disposable cutlery, etc.PVC: a type of plastic used for pipes that carry water and for many other products. PVC is anabbreviation of “polyvinyl chloride.”PVA:PVA is used in many industries, such as the textile, paper industry, and food packaging industries.Bakelite: Bakelite continues to be used for wire insulation, brake pads and related automotivecomponents, and industrial electrical-related applications.

Q101. Type of reactants or product decides the nature of method adapted for finding:

• A. Rate constant
• B. Enthalpy
• C. Temperature
• D. Rate of a reaction✓

Explanation: The correct answer is Rate of a reaction because the methods used to determine reaction rates are significantly influenced by the nature of the reactants and products involved. Different reactants may require different experimental setups or calculations to accurately measure their reaction rates. In contrast, the other options do not reflect this dependency on the nature of the reactants or products. For instance, the Rate constant is a fixed value for a given reaction at a specific temperature and does not vary with different reactants or products, while Enthalpy is a state function that relates to energy changes rather than specific methodologies for measuring reactions. Temperature is indeed a factor, but it does not specifically determine the method used to analyze the reactants or products.

Q102. The rate of reaction:

• A. Increases as the reaction proceeds
• B. Decreases as the reaction proceeds✓
• C. Remains unchanged
• D. None of these

Explanation: The correct answer is that the rate of reaction decreases as the reaction proceeds. This is due to the reduction in reactant concentrations as they are converted into products. Since reaction rate is dependent on the concentration of reactants, a decrease in these concentrations leads to a decrease in the rate. Option A is incorrect because it suggests the rate increases, which contradicts the typical behavior of reactions. Option C is incorrect because it suggests the rate remains unchanged, which is not the case as the reaction typically slows down. Option D is incorrect as Option B provides the correct description.

Q103. Which one of the following has largest ionic radius?

• A. Li+
• B. O22-✓
• C. B3+
• D. F-

Explanation: The ionic radii of elements exhibit the same trend as the atomic radii. The atomic size generally decreases across a period for the elements of the second period. It is because, within the period, the outer electrons are in the same valence shell and the effective nuclear charge increases as the atomic number increases resulting in the increased attraction of electrons to the nucleus. The size of an anion will be larger than that of the parent atom because the addition of one or more electrons would result in increased repulsion among the electrons and a decrease in effective nuclear charge.In given question option A and C are cations in the second period. So they will have less ionic radius than that of the anions of same period. Oxygen falls left to the fluorine and also has one extra negative charge (O2-2) than fluorine ion (F-). Hence, the correct option is (B).

Q104. The velocity constants for the forward and backward reactions are 3.6 × 10⁻⁴ and 1.2 × 10⁻⁵. The equilibrium constant of the reaction is:

• A. 3
• B. 0.033
• C. 0.33
• D. 30✓

Explanation: Equilibrium constant = rate of forward reaction / rate of reverse reaction

Q105. Find the mass in grams of 1.69 mol of phosphoric acid:

• A. 165.6 g✓
• B. 157 g
• C. 148 g
• D. 138 g

Explanation: Moles = Mass / molar mass Moles x molar mass = mass in grams Molar mass of phosphoric acid H₃PO₄ = 98 g / mol 1.69 mol x 98 g /mol = mass in grams Mass = 165.6 g

Q106. What is the unit of Kw for water?

• A. Moles/dm³
• B. Mol²/L²✓
• C. Dm³/moles
• D. Dm³/moles²

Explanation: Kw = [H+] [OH-]The unit for Kw would be:Kw = [mol/L] [mol/L]= mol2/L2

Q107. Bond energy:I. is the energy required to break a bond between two atoms in a diatomic molecule II. Is taken as the energy released in forming a bond form free atoms III. Is the measure of the strength of bond.

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

Explanation: Bond energy is a critical concept in understanding chemical bonding and is defined through multiple perspectives:Option I: It is indeed the energy required to break a bond between two atoms in a diatomic molecule, indicating how much energy is needed to overcome the bond's strength.Option II: The energy released when a bond is formed from free atoms is also a measure of bond energy, showing the stabilization energy provided during bond formation.Option III: Bond energy serves as an indicator of bond strength; stronger bonds require more energy to break, thus having higher bond energies.Therefore, all three options collectively provide a comprehensive understanding of bond energy, making Option E the correct choice. Each statement highlights a different but related aspect of bond energy, and understanding this concept requires integrating all perspectives.

Q108. Atoms in solids are:

• A. Loosely Packed
• B. In random motion
• C. Excited
• D. Closely packed✓

Explanation: Atoms in solids are closely packed together, thus solids maintain rigid shapes.

Q109. Modern periodic table is arranged in ascending order of?

• A. Nucleon number
• B. Atomic mass
• C. Proton number✓
• D. Mass number

Explanation: Elements of the periodic table are arranged in ascending order of their atomic number or proton number (which corresponds to the number of protons in the nucleus). Nucleon number, mass number, or atomic mass (all terms used to describe the same thing i.e. relative atomic mass) may have been used in earlier periodic tables.

Q110. The temperature at which one crystalline form changes to another is called _ temperature.

• A. Critical
• B. Absolute
• C. Transition✓
• D. None of these options is correct

Explanation: Option A: The critical temperature refers to the temperature above which a substance cannot exist as a liquid, regardless of the pressure. This is commonly seen in the context of supercritical fluids.Option B: The absolute temperature is a temperature scale that is based on absolute zero, the theoretical temperature at which all matter would have zero thermal energy. This temperature scale is commonly used in scientific applications.Option C: At the 'Transition temperature' a material changes from one allotropic crystal state to another. To be more specific, at the 'Transition temperature', two crystalline forms of a substance can co-exist in equilibrium.Option D: "None of these options is correct" is also incorrect as the correct answer is (C) Transition.

Q111. A species which is formed by the acceptance of proton by a base is called _.

• A. Acid
• B. Conjugate acid✓
• C. Conjugate base
• D. Salt

Explanation: In the question, you are asked to identify the species formed by the acceptance of a proton by a base, which is called a conjugate acid. It is the species that is created by the addition of a proton to a base during a chemical reaction. In an acid-base reaction, the base accepts a proton to become its conjugate acid. Hence, Option B is the correct answer.

Q112. Select the organic compound which belongs to Arene family:

• A. CH2 = CH2
• B. CH3 - O - CH3
• C. CH3 - NH2
• D. C6H6✓

Explanation: Arene Family (Aromatic Hydrocarbons)Definition:Arenes (aromatic hydrocarbons) are a class of cyclic hydrocarbons that contain one or more benzene rings (C₆H₆) with delocalized π-electrons, making them highly stable.Structure of Benzene (C₆H₆) – The Basic Arene:Hexagonal ring with alternating single and double bonds.Delocalized π-electrons make the ring electron-rich and stable.Resonance hybrid structure, meaning all C-C bonds are equal in length. Types of Arenes:Monocyclic Arenes (Single benzene ring)Benzene (C₆H₆)Toluene (C₆H₅CH₃)Phenol (C₆H₅OH)Aniline (C₆H₅NH₂)Polycyclic Arenes (Fused benzene rings)Naphthalene (C₁₀H₈) – Found in mothballs.Anthracene (C₁₄H₁₀) – Used in dyes.Phenanthrene (C₁₄H₁₀) – Found in coal tar.

Q113. An ester is prepared by:

• A. Two alcohols
• B. Carboxylic acid and alcohol✓
• C. Ketone and alcoho
• D. Aldehyde and alcohol

Explanation: Esters are made by the reaction of a carboxylic acid with an alcohol, a process that is called esterification.

Q114. Hydrolysis of Nitriles produces:

• A. Carboxylic acid✓
• B. Aldehydes
• C. Ketones
• D. Esters

Explanation: The hydrolysis of nitriles, which are organic molecules containing a cyano group, leads to carboxylic acid formation.An example is given below:

Q115. Acetic anhydride is a product of acetic acid, as a result of the following reaction:

• A. Dehydration✓
• B. Reduction
• C. Oxidation
• D. Esterification

Explanation: Acetic anhydride can be prepared by the dehydration of acetic acid at 800°C so, option A is correct.The reduction of acetic acid doesn’t give acetic anhydride, it produces ethanol.Oxidation of acetic acid produces various by-products such as carbon monoxide and carbon dioxide.Esterification of acetic acid produces various esters.

Q116. The unit _ is commonly used by meteorologists.

• A. Bar
• B. Centibar
• C. Millibar✓
• D. Kilobar

Explanation: Millibar is a metric unit of pressure commonly used by meteorologists.

Q117. All the collisions between the particles of gases are elastic in nature. What is meant by "Elastic Collisions"?

• A. No change in the total kinetic energy✓
• B. The velocity of the molecules changes
• C. No change in potential energy during the collisions
• D. No change in mass during the collisions

Explanation: In elastic collisions, the total kinetic energy before and after collision remains the same. Gas molecules may change direction and speed, but energy is conserved. This assumption is a key part of the kinetic molecular theory of gases.

Q118. Which of the following is not an interstitial compound?

• A. Cu-Zn
• B. Cu-Zn-Sn
• C. TiH1.73
• D. V2O5✓

Explanation: V2O5 is not an interstitial compound. Interstitial compounds are those that do not have an exact composition as shown in V2O5. Interstitial compounds are formed when small atoms of H, C, B, or N get trapped inside the crystal lattice of metals/ enter the interstices of transition metals and impart useful features to them. These are non-stoichiometric compounds (their element ratio can’t be represented by a ratio of well-defined numbers.) and are also sometimes termed interstitial alloys. An interstitial alloy is formed when one type of metal atoms are much smaller than the other type. V2O5 is a stoichiometric compound as shown by the formula i.e., one molecule of vanadium pentaoxide has 2 vanadium atoms and 5 oxygen atoms.

Q119. Zinc reacts with dil. H2SO4 to give H2. It also reacts with conc. H2SO4 to form SO2. In these reactions:

• A. Zn reduces H+ to H2
• B. Zn oxidizes H+ to H2
• C. Zn reduces SO42- to SO2
• D. Zn oxidises SO42- to SO2
• E. Both A and C✓

Explanation: Both options A and C are correct.

Q120. Which one of the following ions exhibits d-d transition and paramagnetism as well?

• A. MnO4-
• B. CrO42-
• C. Cr2O72-
• D. MnO42-✓

Explanation: The correct answer is MnO42-, where manganese is in the +6 oxidation state. In this state, manganese retains d electrons, making d-d transitions possible. Moreover, the presence of unpaired electrons in the d orbitals results in paramagnetism.The other options, MnO4-, CrO42-, and Cr2O72-, have their respective metal ions in oxidation states where no d electrons are present (Mn⁷⁺ and Cr⁶⁺). Consequently, these ions cannot exhibit d-d transitions and are not paramagnetic.

Q121. Which of the following reactions is NOT shown by ketones?

• A. Reaction with HCN
• B. Reaction with Fehling solution✓
• C. Reaction with NaHSO3
• D. Reaction with 2,4-dinitrophenyl-hydrazine

Explanation: Fehling's solution is a mixture of Rochelle salt (blue color) and copper sulphate (chso4). It is an oxidizing agent which is used to diffentiate between aldehydes and ketones. Ketones generally do not react with Fehling's solution. A red colored precipetate is formed when Fehling's solution is reacted with aldehyde.Reaction with HCN:Ketones when added with HCN give hydroxynitriles. HCN will be added with the carbon-oxygen double bond to produce hydroxynitriles.Rxn with NaHso3:Ketones generally get added with NaHSO3 by the process of nucleophilic addition.Rxn with 2,4 dinitrophenol hydrazine:Aldehydes and ketones on reaction with this generally form orange/yellow precipitates.

Q122. The common name of the following aldehyde is:

• A. α - Methyl - Ɣ - Chloro Propionaldehyde
• B. β - Chloro - Ɣ - Methyl - Propionaldehyde
• C. β - Chloro - α - Methyl Propionaldehyde✓
• D. β - Methyl - α - Chloro Propionaldehyde

Explanation: Aldehydes take their name from their parent alkane chains. The -e is removed from the end and is replaced with -al. The aldehyde functional group is given the #1 numbering location and this number is not included in the name. For the common name of aldehydes start with the common parent chain name and add the suffix -aldehyde. Substituent positions are shown with Greek letters. When the -CHO functional group is attached to a ring the suffix -carbaldehyde is added, and the carbon attached to that group is C1. The alpha carbon is the carbon adjacent to the carbonyl group or the carbon having an oxygen atom linked to it via a double bond. Beta carbons are the carbons adjacent to the alphas excluding the carbon of the carbonyl group. Lastly, we name the side chains in alphabetical order as shown in the correct option where we have the Chloro group named earlier followed by the methyl group and not the order way around, again because the letter 'C' comes before the letter 'M'.

Q123. The type of isomerism existing in a compound of molecular formula C2H6O is:

• A. Functional group✓
• B. Position
• C. Chain
• D. Metamerism

Explanation: In a compound with the molecular formula C2H6O, which corresponds to ethanol (CH3CH2OH) as well as dimethyl ether ( CH3-O-CH3), the type of isomerism that exists is functional group isomerism. Following groups of organic compounds are functional group isomers of each other;1- Alcohols and ethers2- Aldehydes and ketones3- Carboxylic acids and esters.

Q124. Which of the following compounds show geometric isomerism?

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

Explanation: For geometric isomerism to be possible two adjacent carbon atoms must have two different groups attached to them which is only in the case of B.If both CH3 are above the cyclic structure it is -cis.If CH3 at one carbon and H at the other carbon is above the cyclic structure then the structure will be -trans. A,C and D are all wrong because they don’t satisfy the condition for two adjacent carbons having two different functional groups.

Q125. H2 and Cl2 do not react in the dark, but in the presence of light a vigorous reaction is initiated due to the formation of:

• A. Hydrogen free radical
• B. Chlorine free radical✓
• C. Hydrogen chloride molecule
• D. Both hydrogen and chlorine free radicals

Explanation: To break the covalent bond between two chlorine atoms, photons of ultraviolet rays are required. There is no such requirement for breaking the bond between hydrogen atoms, hence the answer is B.

Q126. Which of the following will react with water?

• A. CHCl3
• B. Cl3CCHO✓
• C. CCl4
• D. ClCH2CH2Cl

Explanation: Cl3CCHO will react with water. Water is a polar solvent. Like dissolves like. A polar solvent will be dissolved in a polar and a non-polar compound will be dissolved in a nonpolar solvent. CCl4, ClCH2CH2Cl are non-polar. So they will not be able to dissolve in water. Cl3CCOOH will form hydrogen bonds with water due to which it will dissolve in water. Such hydrogen bonding is not present in the case of CHCl3. Chloral (Cl3CCHO) reacts with water to form chloral hydrate, CCl3CH(OH)2

Q127. IUPAC Nomenclature of: CH3 - CH = CH - CH2 - CH = CH2 is:

• A. 2 - pentene
• B. 1, 4 - hexadiene✓
• C. 3 - methyl butane
• D. 1, 3, 5 - heptatriene
• E. 1, 3, 6 - hexatriene

Explanation: The correct IUPAC name for the compound CH3 - CH = CH - CH2 - CH = CH2 is 1,4-hexadiene. This is because the compound has a longest chain of 6 carbon atoms, indicated by the prefix 'hex'. The double bonds are located at the first and fourth carbon atoms, which is specified in the name as 1,4-diene. The other options are incorrect because they either miscount the number of carbon atoms, suggest incorrect branching, or provide inappropriate locations for the double bonds.

Q128. What substrates are required to add a NO2 group to benzene?

• A. Concentrated HNO3/Concentrated H2SO4/100˚C
• B. Concentrated HNO3/Concentrated H2SO4/50˚C✓
• C. Concentrated HNO3/50˚C
• D. Concentrated HNO3/100˚C
• E. Concentrated HNO3/Concentrated HCl/50˚C

Explanation: Nitration of benzene involves the substitution of a hydrogen atom on the benzene ring by a nitro group, NO2. The reaction requires the presence of both concentrated nitric acid and concentrated sulfuric acid as reagents, and it is conducted at a temperature not exceeding 50°C. This temperature control is important to avoid side reactions and to ensure the formation of the desired nitrobenzene. The sulfuric acid acts as a catalyst by generating the nitronium ion, NO2+, which is the active electrophile in the reaction. The other options are incorrect because they either exceed the temperature limit, omit the necessary sulfuric acid, or replace it with an ineffective substitute.

Q129. SN2 reaction at an asymmetric carbon of a compound always gives:

• A. An enantiomer of the substrate.
• B. A product with opposite optical rotation.
• C. A mixture of diastereomers.
• D. A single stereoisomer.✓

Explanation: SN2 reaction proceeds with inversion of configuration. Since the attacking nucleophile is not same as that of leaving group, the product cannot be enantiomer of the substrate so the product will not necessarily have opposite optical rotation. Moreover only one product is obtained, so we cannot obtain diastereomers.

Q130. Catalyst used in reaction CHCl3 + ½ O2 → COCl2 + HCl is _ and its nature is _.

• A. 5% methyl alcohol ... negative
• B. 2% Ethyl alcohol ... negative✓
• C. V2O5 … positive
• D. Al2O3 ….. negative

Explanation: The correct catalyst for the reaction CHCl3 + ½ O2 → COCl2 + HCl is 2% ethyl alcohol, which acts as a negative catalyst. This means it decreases the rate of the reaction, aiding in the controlled formation of the toxic gas phosgene (COCl2). Other options like methyl alcohol, V2O5, and Al2O3 are incorrect as they do not fulfil the role of a negative catalyst in this specific reaction.

Q131. The product formed by acid catalysed hydration of 2 - phenyl propene is:

• A. 3 - phenyl - 2 - propanol
• B. 2 - phenyl - 2 - propanol✓
• C. 1 - phenyl - 1 - propanol
• D. 1 - phenyl - 2- propanol

Explanation: The answer is B as we have the phenyl on the second carbon and the double bond being either between carbon number 1 and 2 or between carbon number 2 and 3. Based on the information about the position of the phenyl group, we can rule out options A, C, and D as all three show the phenyl having its position changed which is not possible. Hydration would remove the double bond, replacing it with a hydroxyl group that could be on either three of the carbons. As we only have option B satisfying our condition of the phenyl group being on the second carbon, we can infer the hydroxyl is on the second carbon as well based on the options provided.Also remember, the major product obtained on acid - catalysed hydration of 2-phenylpropene is 2-Phenylpropan-2-ol.

Q132. Which of the following is not a physical property of ethers?

• A. They are usually volatile liquids
• B. Show weak hydrogen bonding
• C. They are highly flammable with low boiling points
• D. It is poisonous and is used as a disinfectant in hospitals✓

Explanation: Ethers are generally volatile liquids with low boiling points because they cannot form strong intermolecular hydrogen bonds. They are also highly flammable. Although they do not hydrogen-bond with themselves, they can form weak hydrogen bonds with water. However, the statement that an ether is poisonous and used as a disinfectant in hospitals is incorrect—this property refers to phenol, not ethers. Therefore, option D is not a physical property of ethers.

Q133. Michael Faraday discovered benzene in the gas formed from?

• A. Destructive distillation✓
• B. Fractional distillation
• C. Steam distillation
• D. Vacuum distillation

Explanation: Michael Faraday discovered benzene in the gas formed from destructive distillation. Destructive distillation is a process in which a substance is heated strongly in the absence of air or oxygen, leading to the breakdown of the compound into smaller, volatile fragments. This process is commonly used to convert complex organic materials, such as coal or wood, into simpler and more useful products. In the case of benzene, it was first discovered by Faraday in the gas produced during the destructive distillation of organic substances.

Q134. One of the reactants consumed earlier than others in a chemical reaction is called:

• A. Active reactant
• B. Excess reactant
• C. Limiting reactant✓
• D. More active reactant

Explanation: In a chemical reaction, the limiting reactant is the reactant that is completely consumed or used up first, thereby limiting the amount of product that can be formed. The other reactants are present in excess, meaning there is more of them than needed to react completely with the limiting reactant. The limiting reactant determines the theoretical yield of the product in the reaction. Hence, option C is correct.

Q135. The color of Mg metal flame is?

• A. Blue
• B. Violet
• C. Yellow
• D. White✓

Explanation: The color of the flame produced burning magnesium metal is a bright white. The high temperature of the flame excites the electrons in the magnesium atoms, causing them to emit visible light. The white color is a result of a broad spectrum of colors being emitted, which combines to give the appearance of white light.

Q136. When a body moves in a circle, the angle between its velocity v and angular velocity ω is always

• A. 0o
• B. 180o
• C. 360o
• D. 90o✓

Explanation: When a body moves in a circle, the angle between its velocity vector (v) and angular velocity vector (ω) is always 90 degrees, or π/2 radians. This is because the velocity vector is tangential to the circle at any point, pointing in the direction of motion, while the angular velocity vector is perpendicular to the plane of the circle and points along the axis of rotation. As a result, the angle between them is always a right angle. Options A, B, and C are incorrect because the angle between velocity and angular velocity in circular motion is not 0, 180, or 360 degrees. The correct angle is always 90 degrees due to the specific geometric relationship between these vectors in circular motion.

Q137. A bus and a car, moving at the same speed, are brought to rest by applying the same retarding force then:

• A. Bus will come to rest in a shorter distance
• B. Car will come to rest in a shorter distance✓
• C. Both will come to rest in the same distance
• D. None of the above

Explanation: The distance they move will depend on their deceleration, which in turn would depend on the frictional force exerted by their respective brakes. If both were to experience the same frictional force 'F', then as per F=ma it is evident that the car having the lesser mass will decelerate faster ( greater magnitude of deceleration) and will therefore come to a halt sooner. Conceptually this is due to the effect of inertia as the bus has a greater mass of two vehicles.

Q138. By burning 1 g of coal, the energy produced is 2 kcal. Then for 1 kWh, the quantity of coal required will be nearly:

• A. 9 kg
• B. 4/5 kg
• C. 2/5 kg✓
• D. 3/14 kg

Explanation: To find out how much coal is needed for 1 kWh, we start by converting kWh to kcal. Since 1 kWh is equivalent to 860 kcal, we can calculate the amount of coal needed. Given that burning 1 g of coal yields 2 kcal, we can compute:Energy from 1 g of coal: 2 kcalEnergy needed: 860 kcalCoal needed = (860 kcal) / (2 kcal/g) = 430 g = 0.43 kg.Since the question asks for the nearest option in kilograms, 0.43 kg is approximately equal to 2/5 kg. Therefore, Option C is correct.Options A, B, and D are incorrect because they either overestimate or underestimate the required amount of coal based on the data provided in the question.

Q139. The extension in a string, obeying Hooke’s law, is x. The speed of sound in the stretched string is v. If the extension in the string is increased to 1.5x, the speed of sound will be:

• A. 1.22V1✓
• B. 0.61v
• C. 1.50v
• D. 0.75v

Explanation: Speed of sound V= square root (T/M)Where m is the mass per unit lengthFrom here we can see that V is proportional to square root (T)Also, T is proportional to xSo, V2/V1 = (1.5x/x)square rootV2= (1.5square root) x V1V2= 1.22V1

Q140. If f1 and f2 are frequencies of two tuning forks, such that f1 < f2, then the number of beats produced in one second is:

• A. f2 - f1✓
• B. f2 x f1
• C. f1 - f2
• D. f2 + f1

Explanation: If the two waves are in phase t=0, they will be in phase when the first wave has gone through exactly one more cycle than the second. This will happen at a time t=T, the period of the beat.Let n be the number of cycles of the first wave in time T, then the number of cycles of the second wave at the same time is (n-1). Hence, T = Nt1 = (n-1)T1.

Q141. A projectile is launched with vertical kinetic energy, K, at an angle of 8. Its variation with kinetic energy is?

• A. Parabolic✓
• B. Periodic
• C. Hyperbolic trajectory
• D. Linear

Explanation: Projectile motion is parabolic because the vertical position of the object is influenced only by a constant acceleration and also because horizontal velocity is generally constant. Put simply, basic projectile motion is parabolic because of its related equation of motion.

Q142. In which situation is distance three times its displacement?

• A. Object moves and come back to its initial position
• B. Object moves 20 m towards east and 10 m towards west✓
• C. Object moves 20 m towards east and 10 m towards south
• D. Object moves 20 m towards north and 10 m towards west

Explanation: When object moves 20 m towards east and 10 m towards west , displacement is 20 _ 10 = 10 m Distance = 20 † 10 = 30 m Here , it clearly shows distance is thrice of displacement.

Q143. Infrasonic waves have a frequency of:

• A. Greater than 20000 Hz
• B. Less than 20 Hz✓
• C. 20 Hz
• D. Greater than 20 Hz

Explanation: Infrasonic waves are waves with frequencies below the human audible range i.e. 20-20000 Hz

Q144. The potential energy at the mean position of a pendulum is:

• A. Half
• B. Maximum
• C. Minimum✓
• D. 75%

Explanation: The potential energy at the mean position of a simple pendulum is minimum i.e. zero. At this point, the entire energy is purely kinetic as the system is at its maximum speed.

Q145. Due to high elasticity, the speed of sound is maximum in:

• A. Solids✓
• B. Liquids
• C. Gases
• D. Plasma

Explanation: The speed of sound is highest in solids because the particles in a solid are closely packed together. This tight arrangement allows sound waves to travel quickly through the solid material.

Q146. The strength of the magnetic field at a point r near a long straight current carrying wire is B. The field at a distance r/2 will be:

• A. B/2
• B. B/4
• C. 2B✓
• D. 4B

Explanation: Following is the solution to this question:

Q147. A liquid has a specific heat capacity c. The rate of change in temperature of the liquid is R. The rate at which heat is transferred from the liquid is P. What is the mass of the liquid?

• A. P/cR✓
• B. PR/c
• C. Pc/R
• D. cPR

Explanation: Since Q=mctAnd according to the question, Q=P, c=c, and t=RWhen we place the values in the equation making m the subjectm=P/cR

Q148. An example of a non-ohmic resistor is:

• A. Diode✓
• B. Tungsten wire
• C. Carbon resistor
• D. Copper wire

Explanation: Diodes are examples of non-ohmic resistors because they do not have a constant resistance and their current-voltage relationship is nonlinear, meaning they do not adhere to Ohm's Law. The resistance changes depending on the voltage across them. On the other hand, tungsten wire, carbon resistors, and copper wire are all examples of ohmic materials. They maintain a constant resistance over a range of voltages and currents, thus complying with Ohm's Law.

Q149. The hot resistance of the bulb's filament is higher than its cold resistance because the temperature coefficient of the filament is _.

• A. Zero
• B. Negative
• C. Positive✓
• D. About 2 ohms per degree

Explanation: For conductors ( like filament ) the temperature coefficient is Positive i.e as the temperature increases collision between electrons and protons increases Finally the resistance also increases.A positive temperature coefficient implies that the resistance of the material increases as the temperature rises. This is the case for most metallic conductors, including the filaments used in light bulbs. When the filament heats up and reaches its operating temperature, its resistance increases due to the positive temperature coefficient. Therefore, the hot resistance of the bulb's filament is indeed higher than its cold resistance because of the positive temperature coefficient.

Q150. An adiabatic change is the one in which:

• A. No heat is added to or taken out of a system✓
• B. No change of temperature takes place
• C. Boyle's law is applicable
• D. Pressure and volume remain constant

Explanation: An adiabatic process is defined as a process in which no heat transfer takes place. This does not mean that the temperature is constant, but rather that no heat is transferred into or out from the system.

Q151. The region that lies between IR and UV regions is called:

• A. Radio waves
• B. None of these
• C. X ray region
• D. Visible light✓
• E. All of these

Explanation: The visible light region falls between the ultraviolet (UV) and infrared (IR) regions on the electromagnetic spectrum. The UV region has a wavelength in the range of 100-400 nm whereas the IR region has a wavelength in the range of 760-1 million nm. The narrow range of 400-700 nm represents rays in the visible light range; rays of wavelengths visible to the human eye.

Q152. If there is a frictional force between two surfaces, then which of the following will be created?

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

Explanation: Friction between two surfaces causes charge separation as electrons are transferred from one material to another. This results in one surface becoming positively charged and the other negatively charged, thus creating an electric field between them. The process does not involve the creation of new charges, as they are simply redistributed from one surface to the other. Option A is incorrect because while friction creates charge, it does not directly create an electric field in the traditional sense. Option C is incorrect because there is no direct relationship between friction and the generation of a magnetic field. Option D is also incorrect since it includes the creation of a magnetic field, which does not occur due to friction.

Q153. The unit of capacitance is:

• A. Farad✓
• B. Volt
• C. Seconds
• D. Ampere

Explanation: The unit of capacitance is farad. Volt, ampere and seconds are units of voltage, current and time respectively.

Q154. Current that fluctuates periodically with time is ------?

• A. DC current
• B. BC current
• C. AC current✓
• D. Magnetic current

Explanation: Alternating current is an electric current that periodically reverses direction and changes its magnitude continuously with time in contrast to direct current which flows only in one direction. Hence, option C is correct.

Q155. If an AC voltage of rms value of 10 volts is applied as input of a half-wave rectifier, then the voltage value of the DC output will be:

• A. 10 V
• B. 10.3 V
• C. 10.7 V
• D. 9.3 V✓

Explanation: Since we have the voltage at AC input, which is 10 V, we just need to subtract this value by the diode drop, which is 0.7 V;10 – 0.7 = 9.3V

Q156. Iodine-131 is used to trace which cancer:

• A. Lungs
• B. Thyroid gland✓
• C. Breast
• D. Liver

Explanation: Your thyroid gland absorbs nearly all of the iodine in your body. Because of this, radioactive iodine (RAI, also called I-131) can be used to treat thyroid cancer.

Q157. Calculate the frequency of photons associated with 500 nm wavelength.

• A. 5 x 1014 Hz
• B. 6 x 1014 Hz✓
• C. 7 x 1014 Hz
• D. 9 x 1014 H

Explanation: The relation between frequency and wavelength is given by v = fλ. Given that, Speed of light = v = 3 x 108 m/s.Wavelength λ = 500 nm.Frequency f = v/λ.= 3×108/ 500×10-9 = "6 × 1014 Hz".

Q158. If a bird catches its prey from a height which was initially at rest then momentum will be conserved for:

• A. Bird
• B. Prey
• C. Either bird and prey
• D. Both bird and prey✓

Explanation: d) Both bird and prey: This is the correct answer. As explained earlier, both the bird and the prey experience changes in their momenta due to the interaction between them. Momentum is not conserved for either the bird or the prey.

Q159. If a particle launched with 5m/s at angle of 45 degree, then time of flight is:

• A. 1.44 s
• B. 0.72 s✓
• C. 0.6 s
• D. 0.5 s

Explanation: Using formula for the time of flightT = 2 visin θ / gT = 2 x 5 sin 45 / 9.8T = 0.72 s

Q160. The Garrison and Garmer experiment indicate?

• A. Interference
• B. Electron diffraction✓
• C. Polarization
• D. Refraction

Explanation: The experiment shows diffraction of electron through metal crystals.

Q161. The earth rotates 360o about its axis in about 24 hours. By how many degrees will it rotate In 2 hours?

• A. 90
• B. 60
• C. 30✓
• D. 15

Explanation: Earth rotates 15 degrees every hour 360/24 = 15Earth rotates 30 degrees in 2 hours 15 x 2 = 30

Q162. Speed of sound does not depend on:

• A. Pressure✓
• B. Density
• C. Adiabatic Index
• D. Amplitude

Explanation: Speed of sound does not change with change in pressure. It depends on temperature, so at the same temperature, even if the pressure was doubled, the speed of sound would remain the same.

Q163. Which of the following forces are only attractive?

• A. Electrostatic forces
• B. Gravitational forces✓
• C. Magnetic forces
• D. Forces between same poles of magnet

Explanation: There is no concept of repulsion in gravitational forces.

Q164. 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.

Q165. 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.

Q166. 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.

Q167. The number of electrons emitted in the photoelectric effect depends upon:

• A. Wavelength of incident light
• B. Frequency of incident light
• C. Energy of incident light
• D. Intensity of incident light✓

Explanation: According to Planck's quantum concept, the intensity of an incident beam (electromagnetic wave) means, the number of photons in the beam. If the intensity of the beam increases, the number of photons increases, hence the number of photo-electrons emitting will increase, per the laws of photoelectric emission.

Q168. In simple harmonic motion, which two quantities are always in opposite directions:

• A. Kinetic energy and potential energy
• B. Kinetic energy and velocity
• C. Velocity and acceleration
• D. Acceleration and displacement✓

Explanation: In SHM, acceleration is directly proportional to displacement. a = - w2 xIn SHM, the acceleration of the oscillating object is directly proportional to its displacement from the equilibrium position, but it acts in the opposite direction. When the object is displaced from its equilibrium position, the acceleration acts towards the equilibrium position, trying to restore the object to its equilibrium position. As the object moves away from the equilibrium position, the acceleration is directed towards it, opposing the displacement.

Q169. Work done is said to be negative if force and displacement are _.

• A. Parallel
• B. Perpendicular
• C. Anti parallel✓
• D. None of these

Explanation: When the direction of motion and force acting on body are opposite i.e anti parallel, the work done is said to be negative.W = Fd W = Fd cos 180° W = -Fd A . W = Fd cos 0° W = Fd B . W = Fd cos 90° W = 0

Q170. If a force of 2 N is applied on charge of 3 Coulomb, the electric field becomes _.

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

Explanation: E = F/q F = 2 N , q = 3 C So , electric field = 2N / 3C

Q171. Value of current in a short circuit is_

• A. Infinite✓
• B. zero
• C. minimum
• D. maximum

Explanation: Option A is correct since, in a short circuit, there is no resistance to the flow of charges so a large number of charges flow in a very short time. Thus, the current becomes infinite. Option B is incorrect since there is a flow of charges in a short circuit so the current is not zero Option C is incorrect since it states that current will be very less which is not true as current will be large Option D is incorrect as the maximum current can even occur with very low resistance. But when almost zero resistance is provided the current flow becomes infinite.

Q172. STATEMENTS:I. The dialogue between Jinnah and Gandhi failed.Il. Indian National Congress and Muslim League tried to join hands, so they will be united.

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

Explanation: Gandhi and Jinnah were unable to reach a decision regarding Pakistan hence the dialogue failed. In order to show a united front to the British as they believe that would help them achieve independence INC and ML tried to join hands(work together). Thus both these statements are effects of independent causes.

Q173. Statements: I. Ms. Kulsoom labelled Mr. Waleed as a deserter. II. Ms. Kulsoom offered an apology.

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

Explanation: Labeling someone a deserter (a serious accusation) could likely lead to consequences or social pressure. Offering an apology suggests that Ms. Kulsoom recognized her action was wrong or caused harm, and she's trying to rectify the situation. Thus, the initial action (labeling) is the cause, and the apology is a direct result (the effect).

Q174. A competition always has:

• A. Reward
• B. Rivals✓
• C. Spectators
• D. Referee

Explanation: Competition may or may not have a Reward, Spectators, or Referee. But competition always has Rivals i.e. the opponents who compete with each other.

Q175. Which word does NOT belong with the others?

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

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

Q176. How many such pairs of letters are there in the word 'HISTORICAL' which have as many letters between them in the word as they have between them in the English alphabet?

• A. Four
• B. Six✓
• C. Five
• D. Eight

Explanation: The correct answer is Six. The pairs that satisfy the condition are: HI, ST, IL, LS, CI, and RT. These pairs have the same number of letters between them in the word 'HISTORICAL' as they do in the English alphabet. For example, 'H' and 'I' have no letters between them in 'HISTORICAL' and none between them in the alphabet as well. Similarly, 'S' and 'T' also follow the same pattern. The other pairs can be verified similarly. Options with four, five, or eight pairs are incorrect because they do not account for all six pairs correctly.

Q177. A book cannot exist without?

• A. Education
• B. Pictures
• C. Pages✓
• D. Qualification

Explanation: A book can still exist if it doesn’t have pictures; it can be a reading book without pictures; it might be a book to read for leisure and not for education; and it might not have any qualifications, but it will still be a book. However, without pages, a book cannot physically exist.

Q178. Find the missing number in the series: 1, 7, 3, 9, 6, 12, 10, 16, 15, ?

• A. 18
• B. 15
• C. 21✓
• D. 20

Explanation: This is an alternating series. The first series (1, 3, 6, 10, 15) increases by +2, +3, +4, +5. The second series (7, 9, 12, 16) increases by +2, +3, +4. The next term belongs to the second series, so it is 16 + 5 = 21.

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

• A. J✓
• B. B
• C. E
• D. T

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

Q180. Passage: There is a group of five students A, B, C, D and E from KIPS college. B and E are good in Dramatics and Computer Science. A and B are good in Computer Science and Physics. A, C and D are good in Physics and History. A and C are good in Physics and Mathematics. D and E are good in History and Dramatics. Who is good in Physics, History and Dramatics?

• A. A
• B. B
• C. C
• D. D✓

Explanation: We need to find the student who is listed in all three subject groups. D is listed as being good at "Physics and History" and also at "History and Dramatics." Combining these, D is good at Physics, History, and Dramatics.