Balochistan Mdcat Mock Paper 3 — Solved Past Paper with Answers

Q1. Choose the correct sentence:

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

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

Q2. 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 captain's team is a singular term. If the noun is singular, use 'is'. If it is plural or there is more than one noun, use 'are'. For example, The cat is eating all of his food. The cats are eating all of their food. Therefore, the error lies in the statement "are practicing very hard". Instead, it should be "is practicing very hard".

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: Since the sentence is in continuous and present tense, the verb will have '-ing' added so it will end up as 'am learning'.

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. 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: Option A : "The...an...a" is incorrect because "the" should only be used for specific nouns, whereas "small house" is non-specific and requires an article "a". The use of "an" is also incorrect because "house" starts with a consonant sound. Option B : "An...a...the" is incorrect because "an" should be used before a word that starts with a vowel sound. "House" starts with a consonant sound and should have "a" before it. Option C: A/an and the are articles. They are types of determiners and they go before a noun. Use "a" before words that start with a consonant sound and "an" before words that start with a vowel sound. The definite article is used before singular and plural nouns when the noun is specific or particular. The signals that the noun is definite, that it refers to a particular member of a group. Option D : "A...an...the" is incorrect because "an" should be used before a word that starts with a vowel sound. However, there is no word in the sentence that requires an article "an".

Q6. I'm now going to give you 10 _ tips for running a really successful website.

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

Explanation: Option A: 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. Option B : Valueless: This answer is incorrect as the tips provided for running a successful website are likely to be valuable and useful for website owners. Option C : Unworthy: This answer is incorrect as the tips provided for running a successful website are likely to be worthy of consideration for website owners looking to improve their website's performance. Option D : Unprofitable: This answer is incorrect as the tips provided for running a successful website may not necessarily be focused on generating profits, but rather on improving the website's overall performance and user experience.

Q7. What is the short form of: We are

• A. We're✓
• B. Were
• C. Wer'e
• D. Were'

Explanation: A contraction is a shortened form of a word (or group of words) that omits certain letters or sounds. In most contractions, an apostrophe represents the missing letters.

Q8. My friend _ (suffer) from cholera since August.

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

Explanation: This suggests an action that started in the past (August) but continues in the present.

Q9. Some of the people waiting in line _ getting impatient.

• A. Is
• B. Was
• C. Are✓
• D. Be

Explanation: Since people is a plural term, 'are' will be used.

Q10. 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: 'The' is the article that should be used as a specific man is being spoken about.

Q11. Select the option which fits appropriately in the blank: Although he studied hard, he couldn't succeed _ getting a high score in his test.

• A. In✓
• B. On
• C. At
• D. To

Explanation: The word 'in' is a preposition. A preposition is, in a sense, a connector. When you use the word 'in' in the sentence, you should notice that it smoothly connects the other words around it. If the word at isn't working as a connector, then it will most likely be working as an adverb.

Q12. Select the option which correctly represents the following word: Who is

• A. Whos
• B. Whose
• C. Who's✓
• D. Whos'

Explanation: The contraction of 'who is' is 'who’s'. The apostrophe is always placed where the letter has been removed. For example couldn't, don't, isn't, you're, she's, it's- which is “it is.”

Q13. Select the option which fits appropriately in the blank: A really sophisticated person would never be _ enough, to think that he is always right.

• A. Reverent
• B. Naive✓
• C. Articulate
• D. Humble

Explanation: If someone always thinks they’re right, that is foolish on their behalf, therefore it would be 'naive' for a sophisticated person.

Q14. They will bake the pies. Which tense is used here?

• A. Present
• B. Past
• C. Future✓
• D. Universal

Explanation: Option A : Present tense would be "They bake the pies" or "They are baking the pies." Option B : Past tense would be "They baked the pies." Option C: The word 'will' indicates future tense. Option D : Universal tense is not a grammatical tense.

Q15. None of them _ able to solve this question.

• A. Is✓
• B. Were
• C. Will
• D. Would

Explanation: Option A: None carry singular verbs so here "is" is the right option. Option B : "Were" is incorrect because it is used for plural subjects or in the past tense. Option C : "Will" is incorrect because it refers to the future tense, which does not apply to this sentence. Option D : "Would" is also incorrect because it is a conditional verb form, and it does not fit the sentence's context.

Q16. What type of sentence is this? Our car broke down, so we came last.

• A. Complex
• B. Simple
• C. Compound✓
• D. Compound-complex

Explanation: A compound sentence is a sentence that connects two independent clauses, typically with a coordinating conjunction like 'and' or 'but'. They're best for combining two or more self-sufficient and related sentences into a single, unified one.

Q17. 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.

Q18. 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 (germ cells/gametes) are cells with only haploid number of chromoses (23). These cells have a different chromosome number and undergo independent assortment hence these cells are different compared to all the other cells in the body.A somatic cell is any cell of the body except sperm and egg cells. Somatic cells are diploid, meaning that they contain two sets of chromosomes, one inherited from each parent. Liver, Muscle and White Blood Cells are all somatic cells with a diploid number of chromoses(46).

Q19. 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'.

Q20. 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, where 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.

Q21. 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.

Q22. Which of the following causes Mad Cow Disease?

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

Explanation: Option A: Prions are abnormal proteins that can cause other proteins in the brain to misfold, leading to neurodegenerative diseases such as Mad Cow Disease. These misfolded proteins accumulate in the brain and cause damage. Option B: Viruses are infectious agents that can cause a wide range of diseases in animals and humans. However, Mad Cow Disease is not caused by a virus. Option C: Bacteria are single-celled microorganisms that can cause various infections and disease. However, Mad Cow Disease is not caused by bacteria. It is primarily associated with prions.

Q23. 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 result of convergent evolution. Analogous organs are a fascinating example of how natural selection can shape organisms to adapt to similar environments, leading to similar solutions to environmental challenges even in species that are not closely related in terms of evolutionary history.

Q24. PS I has chlorophyll a molecule which absorbs maximum light of _ nm?

• A. 600 nm
• B. 650 nm
• C. 680 nm
• D. 700 nm✓

Explanation: PSI (Photosystem I) is a complex of chlorophyll a pigment molecules that absorbs light at a wavelength of 700 nm, which is the far-red end of the visible spectrum. This light energy is then used to drive the electron transfer chain in the light-dependent reactions of photosynthesis, ultimately leading to the production of ATP and NADPH.

Q25. Circulatory system is open type in all of the following except?

• A. Arthropoda
• B. Gastropoda
• C. Pelecypoda
• D. Cephalopoda✓

Explanation: Cephalopoda (squid, octopuses, etc.) have a closed circulatory system, where the blood circulates through a series of vessels and chambers. The closed circulatory system of cephalopods is more efficient than the open circulatory systems of other invertebrates. This is because the blood is pumped through a series of vessels, which helps to distribute it more evenly throughout the body. The closed circulatory system also allows cephalopods to have a more active lifestyle than other invertebrates.

Q26. During meiosis, the homologous chromosomes come together and form pairs, this process is called:

• A. Linkage
• B. Synapsis✓
• C. Pairing
• D. Crossing over

Explanation: Synapsis occurs in the Prophase I of meiosis where we have the two homologous chromosomes coming together to form a pair referred to as a 'Bivalent' or a 'Tetrad'.Linkage is the close association of genes or other DNA sequences on the same chromosome. The closer two genes are to each other on the chromosome, the greater the probability that they will be inherited together. Crossing Over is the swapping of genetic material that occurs in the germline. During the formation of egg and sperm cells, also known as meiosis, paired chromosomes from each parent align so that similar DNA sequences from the paired chromosomes cross over one another.

Q27. 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:

Q28. The organs which are similar in function but differ in structure are called:

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

Explanation: Analogous organs have a similar function but with different embryonic origins and structures. Homologous structures share a similar embryonic origin and thus have the same functions. For example, the bones in a whale's front flipper are homologous to the bones in the human arm. However, a butterfly's or a bird's wings are analogous in comparison but not homologous.

Q29. The infection of lungs is called:

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

Explanation: Emphysema is one of the diseases that comprises COPD (chronic obstructive pulmonary disease). Emphysema develops over time and involves the gradual damage of lung tissue, specifically the destruction of the alveoli (tiny air sacs). It is the infection of lungs.

Q30. Interconversion of carbohydrates, proteins, and lipids in living cells are an example of?

• A. Coordinated catabolic activities
• B. Coordinated anabolic activities
• C. Both a and b✓
• D. None of these

Explanation: Interconversion involves both 'catabolism and anabolism'.

Q31. Which type of bond is not responsible in maintaining the tertiary structure of proteins?

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

Explanation: The tertiary structure of proteins are connected by monomers of amino acid by the peptide bond.The structure is composed of hydrogen bonds, Ionic bonds and other interactions.The glycosidic bond is absent in protein structure.

Q32. Which of the following is a form of asexual reproduction in prokaryotic cells?

• A. Binary fission and mitosis
• B. Binary fission and meiosis
• C. Binary fission and transformation
• D. Binary fission✓

Explanation: Prokaryotic cells divide through a form of asexual reproduction called binary fission. This is a simple process in which chromosomes replicate, as the cell increases in size and the resulting two sets of chromosomes move apart to opposite ends of the cell. The cell constricts in the middle as the plasma membrane is pulled inward and a new cell membrane is formed right down the middle completing the process.

Q33. 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.

Q34. 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.

Q35. 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.

Q36. The uterus of the female reproductive system opens into the?

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

Explanation: The uterus of the female reproductive system opens into the vagina. Vagina is a part of the birth canal and is connected to the uterus via cervix. Structure is shown below.

Q37. 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.

Q38. _ 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.

Q39. 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:

Q40. 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).

Q41. 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.

Q42. Vertebrates belong to phylum chordata because:

• A. They have a vertebral column
• B. The brain is enclosed by the skull
• C. The embryos have gills
• D. The body develops from three germinal layers✓

Explanation: Chordates, including vertebrates, undergo embryonic development with three primary germinal layers: ectoderm, mesoderm, and endoderm. These layers give rise to different tissues and organs, enabling the complex body development seen in chordates.

Q43. In Morgan's linkage experiment, when males and females of 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, crossing of yellow bodied (Y) and white eyed (W) female with brown bodied (Y+) red eyed (W+) male 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 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 (wwmm) female 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.

Q44. Human embryo remains enclosed in:

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

Explanation: The amnion or amniotic sac arises from the epiblast cells of the blastocyst and matures to surround the developing embryo, creating a fluid-filled cavity also referred to as the bag of waters or the membranes. It is a thin but tough, transparent pair of membranes that hold a developing embryo (and later fetus) until shortly before birth.

Q45. Which of the following organs serve 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 anatomical organs that have lost most or all of their original function during the course of evolution, hence they serve no purpose.

Q46. In humans, only one ovum is usually discharged from the ovary at a time. This phenomenon is called?

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

Explanation: Ovulation is the release of a mature egg (ovum) from the ovary, and it typically occurs once during each menstrual cycle in humans. After ovulation, the egg is available for fertilization by sperm, and if fertilization doesn't occur, the egg is expelled from the body during menstruation.

Q47. Hemoglobin 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 hemoglobin, 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 hemoglobin. 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 hemoglobin to support the oxygen-carrying capacity of the developing red blood cells

Q48. The enzyme-substrate complex is formed in which part of the enzyme molecule?

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

Explanation: The enzyme-substrate complex is formed in the binding site of the enzyme molecule. This is the specific region of the enzyme that recognizes and binds to the substrate, leading to the formation of the complex. The binding site is a highly specific region that allows only certain substrates to bind to the enzyme, based on their size, shape, and chemical properties. Once the complex is formed, the catalytic site of the enzyme can then carry out the chemical reaction to convert the substrate into the product.

Q49. 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.

Q50. 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.

Q51. The Light reaction takes place in?

• A. Chloroplast
• B. Grana
• C. Thylakoid
• D. Stroma
• E. A,B and C✓

Explanation: The light reactions of photosynthesis indeed take place in the thylakoid membranes within the chloroplasts of plant cells. Thylakoid membranes are flattened, disk-like structures within the chloroplasts. These membranes house the photosystems and other proteins involved in the light-dependent reactions. Grana are stacks of thylakoid membranes. The arrangement of thylakoids in grana provides a large surface area for the organization of pigments, including chlorophyll, necessary for capturing light energy. The overall process in the thylakoid membranes is crucial for capturing and converting light energy into chemical energy, which is then used in the synthesis of ATP and NADPH. These energy-rich molecules, produced during the light reactions, play a key role in powering the subsequent dark reactions (Calvin Cycle) where carbon dioxide is fixed and organic molecules are synthesized.

Q52. Which of the following is not related to the enveloped virus?

• A. They survive for a short time
• B. Their envelope is not sensitive to sunlight✓
• C. They are tolerant to antibodies
• D. Envelope is derived from host

Explanation: Enveloped virus is a virus that has an outer wrapping or envelope. This envelope comes from the infected cell, or host, in a process called "budding off." During the budding process, newly formed virus particles become "enveloped" or wrapped in an outer coat that is made from a small piece of the cell's plasma membrane.

Q53. Numerous opportunist diseases might attack people suffering from the following diseases?

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

Explanation: Numerous diseases may attack the human body when the immune system of the body is compromised, which occurs in AIDS which is a disease of T-lymphocytes caused by HIV virus.

Q54. The complete, mature and infection virus particle is known as:

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

Explanation: Viruses are a small obligate intracellular parasite, containing either RNA or DNA surrounded by a virus protein coat. A complete virus particle is called a Virion. The main function of the virion is to deliver its DNA or RNA genome into the host cell so that the genome can be expressed in the host cell. So, the correct answer is 'Virion'.

Q55. Cholesterol is:

• A. Animal sterol
• B. C27H46O
• C. 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.

Q56. 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: When a substrate fits into the active site of an enzyme, covalent bonds are typically not formed. The interaction between the enzyme and substrate in the active site is characterized by non-covalent bonds. It's important to note that the enzyme-substrate interaction involves reversible bonds, allowing the substrate to bind and be released, facilitating the catalytic cycle of the enzyme. The formation of covalent bonds is typically reserved for specific reactions, such as during the formation of the transition state or in the catalysis of certain reactions, but it's not a general feature of substrate binding in the active site.

Q57. Which element has a function in opening and closing of stomata?

• A. K✓
• B. Mg
• C. Cu
• D. Fe

Explanation: Potassium (K) is crucial for stomatal function in plants. It opens stomata by entering guard cells, promoting turgidity and pore opening. When potassium exits guard cells, stomata close due to reduced turgor pressure. This regulation enables gas and water vapor exchange through stomata.

Q58. Pinworm is a common name used for which of the following?

• A. Rhabditis
• B. Ancylostoma duodenale
• C. Taenia solium
• D. Enterobius vermicularis✓

Explanation: Pinworm is a common name for Enterobius Vermicularis.

Q59. 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.

Q60. 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.

Q61. A smallest contractile unit of muscle contraction called sarcomere is the area between two?

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

Explanation: The sarcomere is the fundamental unit of contraction and is defined as the region between two Z-lines. Each sarcomere consists of a central A-band (thick filaments) and two halves of the I-band (thin filaments). The I-band from two adjacent sarcomeres meets at the Z-line.

Q62. Which of the following is NOT TRUE about the Human Immunodeficiency virus (HIV)?

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

Explanation: It is a well known fact that HIV virus does cause AIDS.

Q63. In some cases, the blastomere can produce complete embryo so, the cleavage will be:

• A. Spiral and determinate
• B. Spiral and indeterminate
• C. Radial and determinate
• D. Radial and indeterminate✓

Explanation: Cleavage in protostomes is spiral and determinate. 'Spiral' means that the planes of cell division are diagonal to the vertical axis of the embryo. 'Determinate' means that the fate of each blastomere is fixed very early. In deuterostomes, the cleavage is radial and indeterminate. 'Radial' means the planes are either parallel or perpendicular to the vertical axis of the embryo. 'Indeterminate' means that each blastomere can develop into a complete embryo (its fate is not fixed).

Q64. 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: In 1924, Russian biochemist Alexander Oparin claimed that life on Earth developed through gradual chemical changes of organic molecules, in the "primordial soup" which likely existed on Earth four billion years ago

Q65. What is the most important structure between body and brain?

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

Explanation: The explanation for this question is as follow: The spinal cord is the centre for great many reflexes and it serves as a pathway for 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.

Q66. At what times is there a no net gaseous exchange between leaves and the atmosphere?

• A. Day
• B. Night
• C. Dawn and Dusk✓
• D. Midnight

Explanation: Option A: During the daytime, photosynthesis is actively taking place in the presence of sunlight. This process involves the intake of carbon dioxide and release of oxygen, leading to a net exchange of gases between leaves and the atmosphere.Option B: During nighttime, photosynthesis ceases as there is no sunlight available for the process. In the absence of photosynthesis, plants primarily engage in respiration, consuming oxygen and releasing carbon dioxide. This results in a net exchange of gases, where more carbon dioxide is released than oxygen is produced.Option C: At the time of dawn and dusk there is no net gaseous exchange between leaves and atmosphere. At dawn and dusk,when light intensity is low, the rate of photosynthesis and respiration may, for a short time, equal one another. Thus the oxygen released from photosynthesis is just the amount required for cellular respiration. Also, the carbon dioxide released by respiration just equals the quantity required by photosynthesizing cells. At this moment there is no net gas exchange between the leaves and the atmosphere. This is termed as compensation point. Option D: Midnight refers to the middle of the night when it is typically dark, and plants primarily undergo respiration. Similar to nighttime, there is a net release of carbon dioxide and consumption of oxygen during this period.

Q67. 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.

Q68. 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.

Q69. Select a method which causes the oxidation of chemical constituent of a bacterial cell:

• A. Steam
• B. Dry heat✓
• C. Filtration
• D. Radiation

Explanation: Dry heat helps kill the organisms using the destructive oxidation method. This helps destroy large contaminating bio-molecules such as proteins. The essential cell constituents are destroyed and the organism dies. The temperature is maintained for almost an hour to kill the most difficult of the resistant spores.

Q70. Which of the following is TRUE about the structure of a typical bacterium?

• A. It has cell wall
• B. It has cytoplasm
• C. It has genetic material
• D. All of the above✓

Explanation: A typical bacterium has all the structures listed from opinion A-C, including cell wall, cytoplasm and genetic material. Although some bacterias dont have cell walls, the question asks about a typical bacteria, hence option D is correct. Diagramatic representation of all the structures is given below:

Q71. Photophosphorylation takes place in the _ of the chloroplasts:

• A. Stroma
• B. Granum✓
• C. Inner membrane
• D. Outer membrane

Explanation: Photophosphorylation takes place in the thylakoid membrane of the chloroplasts. The thylakoid membrane is a membrane system within the chloroplast that contains chlorophyll and other pigments involved in capturing light energy during the light-dependent reactions of photosynthesis. The chloroplast is an organelle with various compartments, including the stroma, thylakoid membrane, and granum. The thylakoid membrane, where photophosphorylation occurs, is located within the chloroplast and is organized into stacks called grana (singular: granum). The grana contain the thylakoid discs where the light-dependent reactions of photosynthesis, including photophosphorylation, take place.

Q72. 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+).

Q73. 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.

Q74. 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.

Q75. An example of a bacteria requiring low concentration of oxygen is?

• A. Spirochete
• B. Ecoli
• C. Pseudomonas
• D. Campylobacter✓

Explanation: Option A: Spirochetes are a diverse group of bacteria that exhibit a helical or spiral shape. While some spirochetes are microaerophilic, many others can tolerate a wide range of oxygen levels.Option B: Escherichia coli (E. coli) is a facultative anaerobic bacterium, meaning it can survive and grow in both the presence and absence of oxygen.Option C: Pseudomonas is a genus of bacteria known for their ability to adapt to a variety of environmental conditions, including aerobic and anaerobic environments. While some species within the genus Pseudomonas are adapted to low-oxygen conditions, many others are capable of aerobic respiration. Option D: Campylobacter is an example of a bacteria that requires a low concentration of oxygen. It is considered a microaerophilic bacterium, meaning it thrives in environments with reduced levels of oxygen. Campylobacter species are commonly found in the gastrointestinal tracts of animals, including birds and mammals, and can cause infections in humans.

Q76. 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.

Q77. These animals have three germinal layers but no coelom

• A. Flatworms✓
• B. Roundworms
• C. Cnidarians
• D. Chordates

Explanation: Option A: Flatworms, also known as Platyhelminthes, have three germinal layers (ectoderm, mesoderm, and endoderm) but do not possess a true coelom. They have a solid body structure without a fluid-filled body cavity. Instead, they have a parenchyma, which is a loose tissue that fills the space between organs.Option B: Roundworms, also known as Nematodes, are another group of animals that have three germinal layers but lack a true coelom. They have an inner tube-like digestive tract but lack a fully developed body cavity. Instead, they possess a pseudocoelom, which is a partially lined body cavity.Option C: Cnidarians, such as jellyfish, corals, and sea anemones, have three germinal layers but do not have a coelom. They have a sac-like body plan with a central digestive cavity called the gastrovascular cavity. The gastrovascular cavity serves both as a digestive and circulatory system, but it is not considered a true coelom.Option D: Chordates, which include vertebrates (animals with a backbone) and some invertebrates, have three germinal layers and possess a true coelom. Chordates have a well-developed body cavity that is fully lined by mesoderm. Examples of chordates include mammals, birds, reptiles, amphibians, and fish.

Q78. 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.

Q79. 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.

Q80. 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.

Q81. Select an anamniote from the following:

• A. Snake
• B. Parrot
• C. Frog✓
• D. Crocodile

Explanation: Amniotes are tetrapods (descendants of four-limbed and backboned animals) that are characterised by having an egg equipped with an amnion, an adaptation to lay eggs on land rather than in water as the anamniotes (including frogs) typically do. The anamniotes are an informal group of craniates comprising all fishes and amphibians, which lay their eggs in aquatic environments.

Q82. 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 population
• 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: 'Species' are a group of living organisms consisting of similar individuals capable of exchanging genes or 'interbreeding'. Hence, when they no longer interbreed they will not be considered the same species.

Q83. 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.

Q84. 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.

Q85. Which one of the following is the pure carbon compound and used as a reducing agent in industries?

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

Explanation: Pure carbon used as a reducing agent in industries. It is also used in the manufacture of iron and steel Industry. (Reference Sindh text book). Coal tar: A good source of hundreds of organic compounds. Petroleum: It is a viscous liquid composed of components with different boiling points. It contains alkanes,alkenes, cycloalkanes, aromatic hydrocarbons. Also called crude oil. Coal gas: Main product used as fuel. It mainly consists of methane and hydrogen.

Q86. The alloy Duralumin is composed of _ of Al.

• A. 95%
• B. 90%✓
• C. 85%
• D. 80%

Explanation: Duralumin is an alloy made up of 90% aluminium, 4% copper, 0.51% magnesium, and less than 1% manganese.

Q87. 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.

Q88. 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).

Q89. The atomic number is usually equals to _

• A. electrons
• B. protons✓
• C. neutrons
• D. positrons

Explanation: atomic number equals the number of protons in the nucleaus of an atom

Q90. 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.

Q91. In the electrolysis of NaNO3, 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.

Q92. 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.

Q93. Which of the following has the highest reduction potential?

• A. F✓
• B. Li
• C. Cl
• D. Mg

Explanation: Reduction potential is the ability of a substance to get reduced. In other words, it is a measure of a substance's ability to oxidize other substances. In this case, F has the highest reduction potential as it can oxidize Cl, Mg, and Li. Fluorine is the best oxidizing agent that there is. The reduction potentials of the given elements decrease in the following order: F > Cl > Mg > Li.

Q94. The mass number of an atom is:

• A. The number of electrons
• B. The number of neutrons
• C. The number of protons
• D. The number of neutrons and protons✓

Explanation: The mass number of an atom is defined as the sum of protons and neutrons that are present inside the nucleus of an atom. For example, the mass number of carbon is 12.01 amu as it has 6 protons and 6 neutrons in its nucleus.

Q95. 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.

Q96. sp3 hybridization in CH4 gives it _ geometry.

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

Explanation: Tetrahedral geometry is shown by sp3 hybridised orbitals like methane.in the formation of methanethe four hybrid atomic orbitals of carbon overlap seperately with four 1s atomic orbitals of hydrogen to form 4 equivalent C-H bonds.

Q97. 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.

Q98. 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: Explanation Type of reactants or product decides the nature of method adapted for finding rate of reaction.The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time.

Q99. 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 rate of reaction generally decreases as the reaction proceeds. This is because as the reactants are consumed and converted into products, their concentrations decrease. Since the rate of reaction is directly proportional to the concentrations of the reactants, a decrease in reactant concentration leads to a decrease in the rate of reaction.

Q100. In the gaseous state, the distance between the molecules is _ times _ than their diameters.

• A. 200, lesser
• B. 300, lesser
• C. 300, greater✓
• D. 200, greater

Explanation: In gaseous state, the atoms are furthest apart so option A and B are wrong. Between C and D students should remember that in gases, the distance between atoms is 300 times their diameter. This is a fact.

Q101. 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).

Q102. 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

Q103. 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

Q104. 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

Q105. 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 IIII only
• D. II only
• E. I, II and III✓

Explanation: All of the above statements are correct, it is because bond energy is the amount of energy required to break a bond as well when this bond is formed the same amount of energy is released. It thus provides us with an estimate of the strength of the bond.

Q106. 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.

Q107. 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.

Q108. 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.

Q109. 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.

Q110. Select the organic compound which belongs to Arene family:

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

Explanation: Aromatic compounds are also called arenes and the only correct option showing a benzene ring / aromatic compound is option D.

Q111. 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.

Q112. 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:

Q113. 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.

Q114. Boyle's law is stated as:"The product of pressure and volume of a fixed amount of gas at constant temperature is a _ quantity

• A. variable
• B. constant✓
• C. discreet
• D. decreasing

Explanation: According to Boyle’s Law, ‘for a fixed amount of gas at a constant temperature, the product of pressure and volume remains constant.’

Q115. 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: By definition, an 'Elastic collision' describes a collision whereby the total kinetic energy of the molecules is unchanged so, option A is correct. Option B, velocity may or may not change in elastic collisions, and the velocity also changes in inelastic conditions as well. Option C, potential energy is not usually used in the context of elastic collisions. Option D is a correct statement but it holds true for all types of collisions and is not exclusive to elastic collisions.

Q116. 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.

Q117. 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.

Q118. Which one of the following ions exhibits d-d transition and paramagnetism as well?

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

Explanation: In case of: (i) MnO4− , Mn is in the +7 oxidation state which means it has zero d (do) electrons. Hence, there is no d-d transition and no paramagnetism. Its colour is due to charge transfer spectra. (ii) CrO42−, Cr is in the +6 oxidation state which means it has zero d (do) electrons. Hence, there is no d-d transition and no paramagnetism. (iii) MnO4​2− , Mn is in the +6 oxidation state which means there is one d (d1) electron which gives rise to d-d transition and paramagnetism. (iv) Cr2O72− , Cr is in the +6 oxidation state which means it has zero d (do) electrons. Hence, there is no d-d transition and no paramagnetism. Its colour is due to charge transfer spectra. Hence, option C is the correct answer.

Q119. 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.

Q120. 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'.

Q121. Which of the following reagent is used to separate and purify carbonyl and non carbonyl compounds?

• A. HCN
• B. BrMgCH3
• C. NaHSO3✓
• D. H2O

Explanation: When a saturated solution of sodium hydrogen sulphite also called sodium bisulphite is mixed with an impure carbonyl compound, it produces an additional compound with white crystals. That is why sodium bisulphite is used for purification of carbonyl compounds from non carbonyl compounds.

Q122. The type of isomerism existing in a compound of molecular formula C2H6O is:

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

Explanation: A is correct because C2H6O is the formula of ethanol and ethanol exhibits only in two forms which are ethanol and methyl ether. Ethanol and Ether are actually two different functional classifications so we can say that they are functional isomer of one another. B is not right because in position isomerism position of functional group gets changed while functional group is same. C is also wrong because in chain isomerism functional group is same as well as its position.What differs is the carbon chain. D is also wrong because it occurs when different number of carbon chain occur on each side of functional group which is also not the case here.

Q123. 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.

Q124. 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.

Q125. 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

Q126. 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: This hydrocarbon has 6 carbons, so the name must contain Hex. Secondly, we will start counting double bonds from the right because this is where the double bond is closest. The double bond is formed at carbon number 1 and carbon number 4 so it will be 1,4-hexadiene.

Q127. 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 happens when one (or more) of the hydrogen atoms on the benzene ring is replaced by a nitro group, NO2. Benzene is treated with a mixture of concentrated nitric acid and concentrated sulfuric acid at a temperature not exceeding 50°C.

Q128. An SN2 reaction at an asymmetric carbon of a compound always gives:

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

Explanation: During SN2-reaction optical inversion takes place, so in SN2-reaction an asymmetric carbon of a compound always gives a product with opposite optical rotation.

Q129. 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 catalyst in the above reaction is 2% ethyl alcohol with negative nature.

Q130. By fermentation process of starch and by the catalytic enzyme, _ is produced.

• A. Methyl alcohol
• B. Ethyl alcohol✓
• C. Acetyl alcohol
• D. Methanal

Explanation: Starch essentially breaks down to give glucose which undergoes the process of glycolysis to give pyruvate and NADH alongside ATP. Pyruvate undergoes decarboxylation to give ethanal and ethanal is reduced by NADH to give ethanol which is an ethyl alcohol. This is, basically, the summarization of the alcohol fermentation so the answer is B.

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: All of the properties except poisonous and disinfectants are physical properties of ethers. Phenol is considered poisonous and is used as a disinfectant.

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. If a wheel of radius r turns through an angle of 30o, then the distance through which any points on its rim moves is

• A. π/3r
• B. π/6r✓
• C. π/30r
• D. π/180r

Explanation: Explanation is given below: To find the distance through which any point on the rim of a wheel moves when the wheel turns through an angle of 30 degrees, you can use the formula for the arc length of a sector of a circle. The formula is: Arc Length (s) = (θ/360) * 2πr Where: θ is the angle in degrees through which the wheel turns. r is the radius of the wheel. In this case, θ is 30 degrees, and r is the radius of the wheel. Arc Length (s) = (30/360) * 2πr Simplifying: s = (1/12) * 2πr s = (π/6) * r So, the distance through which any point on the rim of the wheel moves when the wheel turns through an angle of 30 degrees is (π/6) times the radius of the wheel, or π/6 times r.

Q137. 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: Explanation is given below:

Q138. The expression for centripetal force is given by:

• A. mrω2✓
• B. m2v2/r2
• C. m2v2/r
• D. mv2/r2

Explanation: The expression for centripetal force is Fc = mv2/r or Fc = mrω2

Q139. 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.

Q140. 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. 3/7 kg✓
• D. 3/14 kg

Explanation: This is the following solution:

Q141. 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. 1.22v✓
• B. 0.61v
• C. 1.50v
• D. 0.75v

Explanation: (SOLUTION1) Speed of sound V= (T/m)square root Where m is the mass per unit length From here we can see that V is proportional to (T)square root Also, T is proportional to x So, V2/V1 = (1.5x/x)square root V2= (1.5square root) x V1 V2= 1.22V1 (SOLUTION 2) Following is the solution to this question:

Q142. A body performing circular motion with a constant speed has a constant:

• A. momentum
• B. angular velocity✓
• C. acceleration
• D. radius vector

Explanation: A body moving along a circular path moves such that it traverses equal arc-length in equal intervals of time. Displacement, velocity and acceleration changes at each point on the trajectory. Hence, the speed is uniform and consequently the angular velocity is constant.

Q143. If f1 and f2 are frequencies of two tuning forks, such that f1 < f2, then number of beats produced in one second are:

• 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.

Q144. A projectile is launched with vertical kinetic energy, K at an angle of 8˚. Its variation with kinetic energy KO 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.

Q145. Projectile, when launched at 90 degree with respect to horizontal, its trajectory is

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

Explanation: Option D is correct. 90 degree launch means throwing object vertically upwards and the whole trajectory of motion won’t be parabolic, instead be linear. Reference;

Q146. 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.

Q147. An object is moving at constant speed, which of the following is always true?

• A. Distance is greater than displacement✓
• B. Distance is lesser than displacement
• C. Distance is equal to displacement
• D. We cannot answer

Explanation: Distance can either be greater than displacement, or equal to it. However, even if both distance and displacement are not equal, distance is always going to be greater than displacement, therefore this situation is the one that prevails.

Q148. 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

Q149. 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.

Q150. 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.

Q151. 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:

Q152. What is the magnetic force on a stationary charged particle in a uniform magnetic field?

• A. Zero✓
• B. F-q
• C. F = qvB
• D. F = ILBsinθ

Explanation: Option A) zero is correct. A stationary charged particle in a uniform magnetic field experiences no magnetic force. This is because the magnetic force on a charged particle is determined by its velocity (v) and the angle (θ) between the velocity and the magnetic field (B) according to the formula: F = qvBsinθ If the particle is stationary (meaning its velocity v is zero), then sinθ is also zero, and as a result, the magnetic force becomes zero (F = 0). So, for a stationary charged particle in a uniform magnetic field, the magnetic force is zero.

Q153. The stator and the rotor of an A.C. motor are connected by a

• A. Copper wire
• B. Silver wire
• C. Aluminum wire
• D. No physical connection between them✓

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

Q154. A liquid has specific heat capacity c. The rate of change in temperature of 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

Q155. The number of diodes in bridge rectifier is

• A. 4✓
• B. 3
• C. 2
• D. 5

Explanation: It is a fact that a bridge rectifier has 4 diodes. It is also called a full wave rectifier.

Q156. An example of a non-ohmic resistor is:

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

Explanation: If a device behaves in a way that is NOT described by Ohm's law, (i.e. the resistance is not constant, but changes in a way that depends on the voltage across it), the device is said to be non-Ohmic. Graphite, copper, and tungsten are ohmic. Therefore, carbon resistors, copper wire, and tungsten are ohmic. Tungsten wire (Option B), carbon resistor (Option C), and copper wire (Option D) are all examples of ohmic resistors because they obey Ohm's law and have a constant resistance for a given current or voltage.

Q157. An electromagnetic wave is propagating along Y-axis. Then:

• A. Oscillating electric field is along X-axis and oscillating magnetic field is along Y-axis.
• B. Oscillating electric field is along Z-axis and oscillating magnetic field is along X-axis.✓
• C. Both oscillating electric and magnetic fields are along Y-axis, but phase difference between them is 90°.
• D. Both oscillating electric and magnetic fields are mutually perpendicular in arbitrary directions.

Explanation: An electromagnetic wave is propagating along Y-axis, then oscillating electric field is along Z-axis and oscillating magnetic field is along X-axis.

Q158. The electric field 'E' and magnetic field 'B' in electromagnetic waves are?

• A. Parallel to each other
• B. Inclined at an angle of 45o
• C. Perpendicular to each other✓
• D. Opposite to each other

Explanation: The electric and magnetic fields (E and B) are in phase, and they are perpendicular to one another and the direction of propagation. For clarity, the waves are shown only along one direction, but they propagate out in other directions too.

Q159. 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.

Q160. An adiabatic change is the one in which _.

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

Explanation: In an adiabatic process, no heat is added or removed from the system. Hence Option A is correct. Reference: PTB, pg#248

Q161. 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.

Q162. 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: When there is a frictional force between two objects, the distribution of charges in the two objects is no more uniform i.e. the net charge on the surfaces of the objects becomes either positive or negative, creating an electric field. Think of it as induction by friction. Also, keep in mind that charges are already present in an object i.e. they can not be created and only negative charges are transferred.

Q163. 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.

Q164. 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.

Q165. 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

Q166. Choose the correct statement for the energy band structure of a semiconductor:

• A. At absolute zero temperature, the conduction band of semiconductor is completely filled and valance band is totally empty
• B. At absolute zero temperature, the conduction band of semiconductor is totally empty and valance band is totally filled✓
• C. At absolute zero temperature, both conduction band and valance band of semiconductor are totally empty
• D. At absolute zero temperature, both conduction band and valance band of semiconductor are completely filled

Explanation: The valence band is fully filled and the conduction band is completely empty at T = 0 K because it is the semiconductor's identity that it becomes an insulator at absolute zero.

Q167. The most penetrating radintions out of the following ls that of

• A. γ-rays✓
• B. α-particles
• C. β-rays
• D. X-rays

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

Q168. 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.

Q169. Calculate the frequency of photon associated with 500 nm wavelength.

• A. 5 x 10^(14) Hz
• B. 6 x 10^(14) Hz✓
• C. 7 x 10^(14) Hz
• D. 9 x 10^(14) Hz

Explanation: The formula used is v = f × λ (where speed of sound is 3.0 x 10^8) so frequency is = 3.0 x 10^8 / 500 x 10^-9 = 6 x 10^14 Hz.

Q170. 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.

Q171. A wagon weighing 1000kg is moving with a velocity 50 km/h on smooth horizontal rails. A mass of 250kg is dropped into it. The velocity with which it moves in km/h now is:

• A. 20 km/h
• B. 60 km/h
• C. 40 km/h✓
• D. 25 km/h

Explanation: The correct option is C) Mass of wagon m=1000 kgInitial velocity of wagon v = 50 km/hInitial linear momentum of the system Pi=mv=1000×50=5×10^4kg km/hLet the final velocity (wagon+ mass dropped) system be V.Final linear momentum of the system Pf=(m+M)V=(1000+250)V=1250VUsing conservation of linear momentum, Pf=Pi∴1250V=5×10^4⟹ V=5×10^4/1250=40 km/h

Q172. Which of the following quantities has no effect on simple projectile motion?

• A. Velocity
• B. Force
• C. Mass✓
• D. Acceleration

Explanation: Mass has no effect on projectile motion.

Q173. 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

Q174. A 1kW motor pumps out water from a well 10 meter deep. What is the quantity of water pumped out per second?

• A. 9.2 kg
• B. 9.5 kg
• C. 10.2 kg✓
• D. 10.8 kg

Explanation: m = (P * t) / (g * h)Now we can plug in the values:Power (P) = 1000 W (1 kW)Time (t) = 1 secondAcceleration due to gravity (g) = 9.8 m/s²Height (h) = 10 metersCalculating:m = (1000 * 1) / (9.8 * 10)m ≈ 10.2 kg

Q175. 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.

Q176. 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

Q177. 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.

Q178. Stationary waves are produced by:

• A. Reflection
• B. Interference✓
• C. Diffraction
• D. Rarefaction

Explanation: It is correct as Stationary waves are produced by the phenomenon of interference, specifically by the superposition (combination) of two waves of the same frequency and amplitude traveling in opposite directions. When these waves meet and overlap, their individual waveforms combine in a way that creates regions of constructive and destructive interference, resulting in a stationary wave pattern. The specific pattern of nodes and antinodes depends on factors such as the frequency, wavelength, and boundary conditions of the system.

Q179. 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.

Q180. Charge inside conductor is:

• A. Possible
• B. Can be greater than zero
• C. Zero✓
• D. Negative always

Explanation: Inside a conductor, the charge is distributed in such a way that the net charge is zero. This is known as electrostatic equilibrium.Inside a conductor in electrostatic equilibrium, the electric field is zero. Any excess charge on the conductor redistributes itself in such a way that the electric field within the conductor cancels out. This ensures that there is no net force acting on the charges inside the conductor, leading to a zero electric field.

Q181. 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.

Q182. 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.

Q183. 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.

Q184. Numbers of electrons emitted in 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: The rate of emission of photoelectrons from a metallic surface is proportional to the intensity of incident light .

Q185. In simple harmonic motion, which two quantities are always in opposite direction?

• 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 x

Q186. 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

Q187. 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

Q188. A constant force of 10 N is applied on a body which causes displacement of 12 cm, what will be the work done?

• A. 120 J
• B. 12 J
• C. 1.2 J✓
• D. 18 J

Explanation: Work done = Force x Distance moved. = 10 x (0.12) = 1.2 J

Q189. The 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 the current will be very less, which is not true as the 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.

Q190. 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

Q191. I. Ms. Kulsoom labelled Mr. Waleed 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: The best way to tackle cause and effect questions is to try to merge the two sectences into one using the format: "sentence 1...As a result,...sentence 2. If the new sentence makes sense, then sentence one is the cause and sentence 2 is the effect. So in this case, we could rewrite the two sentences as:"Ms. Kulsoom labelled Mr. Waleed a deserter. As a result, Ms. Kulsoom offered an apology." This makes sense. She did something wrong and as a result she is apologising. Hence we can say that sentence 1 is the cause, and sentence 2 is the effect.

Q192. 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.

Q193. 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.

Q194. 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: Total Six Pairs They are: 1) HI 2) ST 3) I L 4) LS 5) CI 6) RT *Note that in these six pairs of words the difference in alphabets in-between the letter 'HISTORICAL' and in English alphabets is the same. For example: The alphabets H and I have zero alphabets in between the letter HISTORICAL and zero in English alphabets (A-Z). Same is the case for Pair No 2: (ST). Similarly Pair 3 (IL) have a difference of 2 alphabets in both the letter HISTORICAL and in English alphabets (A-Z). The other 3 follow similar sequence but in a backwards direction. Means the counting should be made from right to left side.

Q195. 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.