Uhs Mdcat 2017 Reconduct — Solved Past Paper with Answers

Q1. Choose the word that best fits in with the meaning of the sentence as a whole.Indolence gives vent to _ disposition in human life.

• A. Static✓
• B. Enthusiastic
• C. Energetic
• D. Filthy

Explanation: Static means to be stationary/to stop. It fits in the question as indolence (laziness) means tonot move and not do work.Enthusiastic and energetic are antonyms and do not fit in.Filthy means dirty which also does not fit in.

Q2. Choose the word that best fits in with the meaning of the sentence as a whole.The Quaid’s _ enthusiasm led the Muslims Indo-Pak to independence.

• A. Simplified
• B. Latent✓
• C. Onerous
• D. Threatening

Explanation: Latent means hidden and can be used to describe enthusiasm.Onerous means a great deal of effort, trouble, or difficulty. Threatening describes a sense of danger. Latent is the only suitable term.

Q3. Choose the word that best fits in with the meaning of the sentence as a whole.He _ the incident to the back of his mind.

• A. Revered
• B. Regulated
• C. Reagitated
• D. Relegated✓

Explanation: Relegated means to assign an inferior rank or position. It can be used here as themeaning of pushing the incident back to his mind, and thus lowering its importance/rank.Revered means respected/honoredReagitated is not a word.

Q4. Choose the word that best fits in with the meaning of the sentence as a whole.She managed to _ a ticket for the cricket match.

• A. Procure✓
• B. Obscure
• C. Improvise
• D. Preclude

Explanation: Procure means to obtain.Obscure means unclear.Improvise means to produce or make (something) from whatever is available.Preclude means to prevent it from happening; make it impossible. Hence, option A is the most appropriate.

Q5. Select the wrong segment in the following sentence:She looked at him, and he seemed almost as younger as their eldest son.

• A. Looked at
• B. Seemed
• C. Almost as younger✓
• D. Their eldest

Explanation: "She looked at him, and he seemed almost as young as their eldest son." will be the correct statement.

Q6. Twice, my father stopped to wipe the sweat from his eyes.

• A. Father stopped
• B. Wipe the
• C. From
• D. His eyes
• E. No error✓

Explanation: The sentence 'Twice, my father stopped to wipe the sweat from his eyes.' is grammatically correct and conveys a clear action. Each part of the sentence contributes to its overall meaning without any syntactical or grammatical mistakes. Options A through D each focus on specific segments of the sentence that are indeed correct; however, they do not identify any errors, making them incorrect answers to the question.Thus, the correct choice is Option E: 'No error', as it accurately reflects that there is no mistake in the sentence.

Q7. Spot the error.A tree slid down the slope, leaned against and settled heavily to the ground.

• A. Down
• B. Leaned against
• C. Heavily
• D. To the ground✓

Explanation: The correct statement will be 'A tree slid down the slope, leaned against and settled heavily on the ground.' The error lies in the phrase 'to the ground.' The preposition 'on' is appropriate here to indicate where the tree settled. Options A, B, and C are all correct phrases within the context of the sentence and do not contain any errors.

Q8. Spot the error. The latter continued: “You see how is it- Ralston filled the place up with young men.”

• A. Latter
• B. How is it✓
• C. Up
• D. With

Explanation: The correct phrasing should be 'You see how it is - Ralston filled the place up with young men.'The error lies in the phrase 'how is it,' which disrupts the expected structure of the sentence. The correct form, 'how it is,' maintains proper syntax and clarity.Option A, 'latter,' is not the error since it correctly indicates the second person being discussed. Option C, 'up,' is used correctly and does not contain an error, as does Option D, 'with.' Both are valid phrases in this context.

Q9. Spot the error. The delegates in Anatolia could transfer their activities to Istanbul, put Mustafa Kamal’s ideas into practice and yet not longer stand in opposition to the Padishah.

• A. In
• B. To
• C. Into
• D. Not longer✓

Explanation: "No longer" would be correct form of expression in this sentence. The correct sentence is, "The delegates in Anatolia could transfer their activities to Istanbul, put Mustafa Kamal’s ideas into practice and yet no longer stand in opposition to the Padishah."

Q10. Female workers are entitled 56 days rest on full salary before giving birth to children.

• A. Entitled✓
• B. 56 days rest
• C. On full salary
• D. Giving birth

Explanation: "Entitled to" will be the correct expression. The correct sentence is Female workers are entitled to 56 days rest on full salary before giving birth to children."

Q11. Complete the sentence using the most suitable preposition.You can play as long as you want to but _ this area only.

• A. Inside
• B. Within✓
• C. On
• D. In

Explanation: Within will be the correct preposition to refer to a boundary.

Q12. Choose the correct the sentence from the following options:

• A. You can’t satisfy you're conscious by writing a cheque for a few guineas.
• B. You can’t satisfy conscience by writing a cheque for a few guineas
• C. You can’t satisfy your conscience by writing a check for a few guineas.
• D. You can’t satisfy your conscience by writing cheque of a few guineas.✓

Explanation: You can’t satisfy your conscience by writing cheque of a few guineas. This sentence makes sense and is gramatically correct.

Q13. Choose the correct the sentence from the following options:

• A. He was drenched with the hotness of his fear.
• B. He was drenched in the hotness of his fear.✓
• C. He was drenched by the hotness of his fear.
• D. He was drenched of the hotness of his fear.

Explanation: Whenever drenched is used, it should be drenched in because you are immersed in that thing, for example drenched in water.

Q14. Choose the correct the sentence from the following options:

• A. Don’t you stuff your head with things you do not understand.✓
• B. Don't you scruff youth heard with things you do not understand.
• C. Don't you stuff your head for things you do not understand?
• D. Don’t you stuff your head in things you do not understand.

Explanation: B is wrong because of scruff and youthC is wrong because for and ? should not be used.D is wrong because of in.

Q15. Choose the correct the sentence from the following options:

• A. Mr. Bittering raised the mirror to his face.✓
• B. Mr. Bittering raised the mirror for this face.
• C. Mr. Bittering rised the mirror by his face.
• D. Mr. Bittering raised the mirror into his face.

Explanation: B is wrong because of for.C is wrong because rise is not the correct verb.D is wrong because of the wrong preposition: into.

Q16. Select the most suitable synonym for the given word:MOTIF:

• A. Tough
• B. Stuff
• C. Motion
• D. Design✓

Explanation: Motif: a decorative image or design, especially a repeated one forming a pattern. A, B, and C are not applicable here.

Q17. Select the most suitable synonym for the given word:INIQUITY:

• A. Inequality
• B. Injustice
• C. Wickedness✓
• D. Efficiency

Explanation: Iniquity means immoral and unjust behavior, which is the same as wickedness.

Q18. Select the most suitable synonym for the given word:RECKLESS:

• A. Useless
• B. Careless✓
• C. Dauntless
• D. Fearless

Explanation: Feckless means to be careless. Option B is the most suitable answer.

Q19. Select the most suitable synonym for the given word:MOSAIC:

• A. Pattern✓
• B. Mortal
• C. Ordinary
• D. Musical

Explanation: A mosaic refers to a piece of art with repeating pattern. Option A is the most suitable answer.

Q20. Select the most suitable synonym for the given word:INSCRUTABLE:

• A. Immoral
• B. Unethical
• C. Enigmatic✓
• D. Unaccountable

Explanation: Inscrutable means something that cannot be deciphered/understood so the answer would be C i.e, enigmatic which also refers to something mysterious.

Q21. Select the most suitable synonym for the given word:JUXTAPOSE:

• A. Justify
• B. Compare✓
• C. Expose
• D. Jettison

Explanation: Juxtapose means to compare two contrasting things/traits. Option B is the correct answer.

Q22. Select the most suitable synonym for the given word:EMPATHY:

• A. Fictitious
• B. Facility
• C. Ability
• D. Felicity✓

Explanation: Empathy is most closely described as felicity which means the ability to find appropriateexpression for one's thoughts.

Q23. Select the most suitable synonym for the given word:EVANESCENT:

• A. Evident
• B. Permanent
• C. Event
• D. Transitory✓

Explanation: Evanescent means transitory, something not permanent in its existence. Quickly fading or disappearing. Hence, D is the correct option.

Q24. Select the most suitable synonym for the given word:MUSE:

• A. Wander
• B. Fonder
• C. Robust
• D. Ponder✓

Explanation: Muse and ponder both mean to think. Hence, D option is the right option.

Q25. Choose the best synonym for the following word:Friend

• A. Foe
• B. Brother
• C. Family
• D. Acquaintance✓

Explanation: Acquaintance refers to a person known to one, but usually not a close friend. This is not the exact synonym of friend, but definitely the closest one from all the given options.

Q26. Give the general formula of monosaccharides and polysaccharides.

• A. (CH2O)n and Cn(H2O)2n
• B. (CH2O)2n and Cn(H2O)n
• C. (CH2O)n and Cn(H2O)n-1✓
• D. (CH2O)n-1 and Cn(H2O)n+1

Explanation: Monosaccharides are simple sugars.They have the general formula (CH2O)n, where "n" is the whole number from three to many thousands.Polysaccharides are formed by monosaccharide units bound together by glycosidic linkage.The general formula for polysaccharides is Cn(H2O)n-1.

Q27. The type of carbohydrate which has high molecular weight and is sparingly soluble in water is:

• A. Monosaccharides
• B. Disaccharides
• C. Polysaccharides✓
• D. Maltose

Explanation: Polysaccharides are polymeric carbohydrate molecules composed of long chains of monosaccharide units bound together by glycosidic bonds. They occur as components of high molecular weight compounds significantly less soluble in water due to the absence of hydrogen bonds.

Q28. Among the following, which acid is an unsaturated acid:

• A. Butyric Acid
• B. Oleic Acid✓
• C. Palmitic Acid
• D. Both Oleic Acid and Palmitic Acid

Explanation: •A saturated fatty acid is one that lacks double bonds. Animal fat is commonly composed of saturated fatty acids. They are solid at room temperature.•Unsaturated fatty acid is one that has one or more double bonds in them. They are commonly found in plants and exist in liquid form at room temperature. Oleic acid has a double bond between C9 and C10, making it unsaturated.

Q29. Backbone of amino acids comprises of

• A. R group
• B. Amino group
• C. Carboxylic group
• D. Amino group, carboxylic group, hydrogen atom and R group.✓
• E. None of these

Explanation: Amino acids are molecules that combine to form proteins.Each amino acid contains an amino group,a carboxylic group,an r group and a hydrogen atom which is attached to the central alpha carbon.All of them form the basic skeleton of amino acids.

Q30. The sequence of amino acids is major factor in which type of protein classification;

• A. Primary Proteins✓
• B. Secondary Proteins
• C. Tertiary Proteins
• D. Both Primary and Tertiary Proteins

Explanation: •Primary structure of protein is the simplest level of protein structure.It comprises the number and sequence of amino acids in a protein molecule. For Example:Dystrophin has an important primary structure. •Secondary structure is formed because of hydrogen bonding between amino acids in the peptide chain. For Example:Alpha helices and beta pleated sheets. Tertiary structure is maintained by three types of bonds;hydrogen bond,ionic and disulphide(-S-S-). For Example:Myoglobin •In quaternary structure,tertiary proteins are held together by hydrophobic interactions,hydrogen and ionic bonds. For Example:Hemoglobin

Q31. What is the subunit of DNA:

• A. Phosphoric Acid
• B. Base
• C. Nucleotide✓
• D. Sugar

Explanation: A nucleotide is the basic building block of nucleic acids(DNA and RNA).•It is composed of pentose sugar,phosphate and a nitrogenous base.•The four nitrogenous bases in DNA are Adenine,Guanine,Cytosine and Thymine.Options A,B and D are incorrect because all of them are subunits of the nucleotide itself,not DNA.

Q32. The type of bonding in 𝛼-Helix;

• A. 1,2 Glycosidic Linkage
• B. Ionic Bond
• C. Disulfide Bond
• D. Hydrogen Bond✓

Explanation: The alpha helix is basically found in secondary protein structures.•It is stabilized by hydrogen bonds between the carbonyl oxygen of one amino acid to the amino group of the second amino acid.•Ionic bonds are formed when a positively charged ion forms a bond with a negatively charged ion,one atom transfers the electron to the other one.For Example:Bond between sodium and chlorine.•A disulphide bond is a covalent bond between 2 sulfur atoms (-S-S-).Example:Cysteine,one of the 20 amino acids contains this kind of linkage. •Hydrogen bond is formed when a hydrogen atom forms a bond with a highly electronegative atom (N,O,F).For Example:Bonding between H2O molecules,HF etc.•1,2-Glycosidic linkage is found in sucrose which is a carbohydrate,but alpha helix is included in proteins.

Q33. Enzymes have what effect on the end-product?

• A. They alter the product
• B. The nature of the product is completely changed
• C. No effect✓
• D. The end product is not obtained

Explanation: Enzymes are biocatalysts that speed up chemical reactions by lowering activation energy. Due to this, the products are formed at a faster rate. But enzymes only affect the rate of reaction without being used up, they can't alter the structure of the final product. Options A, B, and D are incorrect because enzymes function as catalysts only in biochemical reactions.

Q34. Lock and Key model was explained by:

• A. Koshland
• B. Emil Fischer✓
• C. De Duve
• D. Golgi

Explanation: The lock and Key model was given by Emil Fischer in 1890.According to this model, the active site is a rigid structure. As one specific key can open only a single lock, in the same way, a specific enzyme can transform a specific substrate into the product(s).Example: Urease is the enzyme that follows this model. This model explains the specificity of enzyme action.

Q35. Name the inhibitors which can be neutralized by adding more substrate:

• A. Competitive Inhibitors✓
• B. Permanent inhibitors
• C. Non-competitive inhibitors
• D. Irreversible inhibitors

Explanation: A competitive inhibitor is a substance similar in structure to an enzyme's substrate that binds to the active site and inhibits a reaction.It blocks the active site of an enzyme and by increasing the concentration of substrate,the effect of a competitive inhibitor can be neutralized.For Example:Malonic acid is a competitive inhibitor of enzyme succinic dehydrogenase.On the other hand, the irreversible inhibitor doesn't compete with the natural active site for substrate but it combines with the site other than the active site.For Example:Cyanide action on cytochrome oxidase.

Q36. What is the percentage of lipids in the chemical composition of plasma membrane?

• A. 60-80%
• B. 20-40%✓
• C. 40-80%
• D. 20-60%

Explanation: The plasma membrane is the outermost covering of an animal cell. Cell membrane is composed of lipids and proteins;60-80% are proteins, while 20-40% are lipids.

Q37. A complex network of channels extending from plasma membrane to nuclear membrane:

• A. Mitochondria
• B. Lysosomes
• C. Endoplasmic reticulum✓
• D. Golgi Apparatus

Explanation: The endoplasmic reticulum is a continuous membrane system that forms a series of flattened sacs within the cytoplasm of eukaryotic cells and serves multiple functions including the synthesis, folding, modification, and transport of lipids and proteins.

Q38. The group of ribosomes joined by mRNA is called as:

• A. Monosome
• B. Polysomes✓
• C. Polypeptide
• D. Lysosome

Explanation: Polysome is defined as the cluster of ribosomes held together by a strand of mRNA that each of them is translating.•Polysomes/Polyribosomes can be found in three forms: free, cytoskeletal-bound, and membrane-bound.

Q39. Which organelle has two subunits?

• A. Endoplasmic reticulum
• B. Ribosomes✓
• C. Nucleus
• D. Plastids

Explanation: Ribosomes are made of proteins and ribonucleic acid. Ribosomes consist of two major components: the small and large ribosomal subunits. The tinier subunit is the place the mRNA binds and decodes, whereas the bigger subunit is the place the amino acids are included.

Q40. Ribosomes in prokaryotes sediments at:

• A. 40S
• B. 70S✓
• C. 80S
• D. 60S

Explanation: All prokaryotes have the 70S (where S is the Svedberg unit used in ultracentrifugation) ribosomes while eukaryotes contain larger 80S ribosomes in their cytosol.

Q41. Identity the common organelle in plant and animals.

• A. Plastids
• B. Chromoplasts
• C. Mitochondria✓
• D. Leucoplasts

Explanation: Mitochondria are membrane-bounded organelles that generate the energy needed to power cells' biochemical reactions which are stored in a small molecule called ATP. They are present in both plants and animals.

Q42. Which function is associated with lysosomes?

• A. Oxidative enzymes production
• B. Conversion of fatty acids to carbohydrates
• C. Phagocytosis✓
• D. Both “Conversion of fatty acids to carbohydrates” and “Phagocytosis”

Explanation: A lysosome is a membrane-bounded organelle that contains digestive enzymes. They are involved in intracellular digestion, the breakdown of excess or worn-out parts of cells, destroy invading viruses and bacteria, autophagy, and phagocytosis.

Q43. Engulfing of solid particle is termed as:

• A. Engulfing
• B. Pinocytosis
• C. Phagocytosis✓
• D. None of the given options

Explanation: Phagocytes are cells that have the ability to ingest, and sometimes digest, foreign particles, such as bacteria, carbon, dust, or dye. They engulf foreign bodies by extending their cytoplasm into pseudopods (cytoplasmic extensions like feet), surrounding the foreign particle and forming a vacuole. Pinocytosis is a process by which liquid droplets are ingested by living cells. Phagocytosis is hence called cell eating and pinocytosis is called cell drinking.

Q44. The site for the synthesis of ribosomal RNA is:

• A. Nucleus
• B. Cytosol
• C. Nucleolus✓
• D. Endoplasmic Reticulum

Explanation: Molecules of rRNA are synthesized in a special region of the cell nucleus called the nucleolus, which appears as a dense area within the nucleus and contains the genes that encode rRNA.

Q45. Among the following, which organelle has an outer membrane in it?

• A. Cell Membrane
• B. Mitochondria✓
• C. Lysosome
• D. Vacuole

Explanation: Mitochondria is an organelle that has a double membrane around it. The outer membrane surrounds the whole organelle. It has many protein-based pores that are big enough to allow the passage of ions and molecules. Inner membrane of mitochondria has Fo-F1 particles located towards the matrix side. Between the outer and inner layers, there is intermembrane space.

Q46. Size of virus ranges in:

• A. 20 to 250 nm✓
• B. 25 to 250 nm
• C. 25 to 300 nm
• D. 20 to 300 nm

Explanation: Viruses are so small that they can't be seen with the naked eye and they can pass through porcelain fibers while most bacteria cannot pass through them. So their range should also be very small in nm.

Q47. Reverse transcriptase is the function of:

• A. Pox virus
• B. HIV✓
• C. Paramyxovirus
• D. Tobacco mosaic virus

Explanation: Reverse transcriptase is an enzyme that converts the RNA genome carried in the retrovirus particle into double-stranded DNA. •This enzyme is found in retroviruses(HIV). •Without reverse transcriptase, the viral genome would not be able to be incorporated into the host cell, resulting in failure to replicate. •Options A, C, and D are incorrect because they don't have reverse transcriptase enzymes.

Q48. When cocci form long chain of cells, the arrangement is termed as:

• A. Staphylococcus
• B. Sarcinae
• C. Streptococci✓
• D. Cocci

Explanation: Pair of cocci are, called diplococci Rows or chains of cells are called streptococci. Grapelike clusters of cells are staphylococci. Packets of eight or more cells are, sarcinae. Group of four cells in a square arrangement is tetrad.

Q49. Which type of bacteria has less amount of lipids in them:

• A. Positive bacteria
• B. Negative bacteria
• C. Gram-negative
• D. Gram-positive✓

Explanation: Gram-positive bacteria have a thick peptidoglycan layer and no outer lipid membrane which gives a positive result in the gram stain test appearing purple. Gram-negative bacteria have a thin peptidoglycan layer and an outer lipid membrane that appears pink.

Q50. Which of the following characteristics belong to mycorrhizae:

• A. Fungi and algae
• B. Alage and root
• C. Fungi and lichen
• D. Fungi and root✓

Explanation: Mycorrhizae is a mutual symbiotic association between a fungus and a plant. The fungi facilitate the uptake of phosphorus and trace metals such as zinc and copper. The plant makes organic molecules such as sugars by photosynthesis and supplies them to the fungus. It accounts for 90% of the flowering plants.

Q51. The site where Ascaris is present:

• A. Intestine✓
• B. Caecum
• C. Stomach
• D. Rectum

Explanation: Ascaris lumbricoides is an intestinal parasite of humans. Their common name is roundworms. Ascariasis is the most common roundworm infection. The larvae and adults live in the small intestine and cause infection.

Q52. The intermediate host for Taenia (tapeworm) is:

• A. Fish
• B. Pig✓
• C. Anemone
• D. Coral

Explanation: Pigs serve as an intermediate host for Taenia solium; humans are infected when they ingest an immature tapeworm(a cysticercus) in undercooked pork; leading to harboring of adult sexually active worms within the intestinal tract.

Q53. Which one is correctly matched with the tail of a phospholipid?

• A. Hydrophilic
• B. Hydrophobic✓
• C. Light absorbing
• D. Porphyrin ring

Explanation: All of the lipid molecules in the cell membrane are amphipathic; that means that they have a hydrophillic(water-loving) or polar head and a hydrophobic (water-fearing) or non-polar tail.

Q54. Graph which shows effectiveness of absorbed light is called:

• A. Emission Spectrum
• B. Effective Spectrum
• C. Absorption Spectrum
• D. Action Spectrum✓

Explanation: Action spectrum shows the wavelength of light absorbed by each pigment i.e. it shows the overall rate of photosynthesis at each wavelength of light. An absorption spectrum is a graph that shows the absorption of different wavelengths of light by a particular photosynthetic pigment.

Q55. Which light is mostly absorbed by chlorophyll-a?

• A. Violet Light✓
• B. Green Light
• C. Red Light
• D. Yellow Light

Explanation: Chlorophyll-a is the primary form of chlorophyll used in photosynthesis. It is blue-green in color and absorbs light mostly in violet-blue and orange-red light. It absorbs the most energy from the wavelength of violet light.

Q56. The term glycolysis refers to the conversion of:

• A. Pyruvate to Glucose
• B. Glucose to Pyruvate✓
• C. Citric acid to CO2
• D. Both Pyruvate to Glucose and Glucose to Pyruvate

Explanation: The term "glycolysis" refers to the conversion of glucose into pyruvate. Glycolysis is the initial stage of cellular respiration, and it takes place in the cytoplasm of cells. The process involves a series of enzymatic reactions that break down one molecule of glucose, a six-carbon sugar, into two molecules of pyruvate, each containing three carbon atoms.

Q57. In Citric Acid Cycle Acetyl CoA combines with:

• A. Glucose
• B. CO2
• C. Rubisco
• D. Oxaloacetate✓

Explanation: In the citric acid cycle (also known as the Krebs cycle or tricarboxylic acid cycle), acetyl-CoA combines with oxaloacetate to initiate the cycle. This condensation reaction is catalyzed by the enzyme citrate synthase. This reaction marks the beginning of the citric acid cycle. Citrate is a six-carbon compound, and as it undergoes a series of reactions, carbon atoms are released as carbon dioxide, and high-energy electrons are transferred to carrier molecules NADH and FADH2. The cycle ultimately regenerates oxaloacetate, which can combine with another molecule of acetyl-CoA to continue the cycle. The citric acid cycle is a key component of cellular respiration, generating NADH, FADH2, and ATP.

Q58. Which one is is CO2 acceptor:

• A. Water
• B. Chlorophyll
• C. CO2
• D. Rubisco✓

Explanation: In the Calvin cycle, the carbon dioxide acceptor molecule is RUBP and the enzyme catalyzing this reaction is RUBP carboxylase. •In this process, the reduction of carbon dioxide gives the first stable product, a three-carbon compound, which is 3-phosphoglyceric acid or 3-PGA.

Q59. Name the structure from which the appendix is formed:

• A. Duodenum
• B. Caecum✓
• C. Kidney
• D. Rectum

Explanation: The vermiform appendix is a blind-end structure that extends from the caecum(the first part of the large intestine). It doesn't have any vital function in the human body, but contains large lymphoid masses that may be useful during childhood. It is now considered a vestigial structure. It must be removed when it is swollen or infected, and its purification is known as appendicitis.

Q60. Identify the cells which secretes HCl:

• A. Parietal cells
• B. Oxyntic cells
• C. Zymogen cells
• D. Both Parietal cells and Oxyntic cells✓

Explanation: Parietal cells are epithelial cells in the stomach that secrete hydrochloric acid(HCl) and intrinsic factors. These cells are found in the lining of the fundus and body regions of the stomach. They are also known as oxyntic cells.

Q61. The site where the most absorption of digested food takes place:

• A. Large intestine
• B. Small intestine✓
• C. kidney
• D. Duodenum

Explanation: The ileum, which is part of the small intestine, is involved in the absorption of digested food. While duodenum and jejunum are involved in the digestion of undigested food that comes from the stomach. About 95 percent of nutrient molecules are absorbed in the small intestine.

Q62. In the oral cavity, the main function of sodium bicarbonate is:

• A. To act as antiseptic
• B. To stabilize the pH of food✓
• C. To act as lubricant
• D. To make a slimy food

Explanation: In the oral cavity, sodium bicarbonate present in saliva acts as a buffer. It neutralizes acids and helps maintain a stable pH, protecting teeth and oral tissues.

Q63. The site of gaseous exchange in humans is:

• A. Bronchioles
• B. Trachea
• C. Alveolar Sacs
• D. Alveoli✓

Explanation: The site for gaseous exchange is the alveoli. Inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.•Options A, B, and C are incorrect as they function as passages for airflow to alveoli. The pathway of airflow isNostrils>Larynx>Trachea>Bronchi>Bronchioles>Alveolar sacs>Alveoli

Q64. The disease in which there is a breakdown of thin walls of alveoli:

• A. Asthma
• B. Emphysema✓
• C. Tuberculosis
• D. Cancer

Explanation: In emphysema, the inner walls of the air sacs are damaged, causing them to eventually rupture. This creates one larger air space instead of many small ones and reduces the surface area available for gas exchange.The main cause of emphysema is long-term exposure to airborne irritants. •In Asthma, the air passages in the lungs become narrow due to inflammation and tightening of the air passage. •Tuberculosis is due to bacterial infection which spreads through tiny droplets from the cough or sneeze of an infected person. •Cancer is due to a mutation in genes.

Q65. The amount of CO2 exhaled from lungs during expiration is:

• A. 4%✓
• B. 0.04%
• C. 0.4%
• D. 0.0045%

Explanation: Exhaled air contains 4.0% carbon dioxide.

Q66. Gaseous exchange in animals takes place through:

• A. Active Transport
• B. Osmosis
• C. Diffusion✓
• D. Active Transport and Diffusion

Explanation: In animals, oxygen and carbon dioxide move by diffusion across moist membranes. In simple animals, the exchange occurs directly with the environment. But with complex animals, such as mammals, the exchange occurs between the environment and the blood. During gas exchange oxygen moves from the lungs to the bloodstream via diffusion. At the same time, carbon dioxide passes from the blood to the lungs. This happens in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.

Q67. Among the following, identify the agranulocytes:

• A. Neutrophils
• B. Basophils
• C. Monocytes✓
• D. Both Neutrophils and Basophils

Explanation: Lymphocytes and monocytes are the two types of agranulocytes or nongranular leukocytes.These white blood cells have no obvious granules. Agranulocytes typically have a largernucleus due to the lack of noticeable cytoplasmic granules.Neutrophils, eosinophils, and basophils are granular leukocytes.

Q68. Bicuspid valve is present between:

• A. Left atrium and left ventricle✓
• B. Right atrium and left ventricle
• C. Left atrium and right ventricle
• D. Right ventricle and right ventricle

Explanation: A bicuspid valve has only two leaflets (flaps or cusps), instead of three. Normally, the mitral valve is theonly bicuspid valve, and this is situated between the heart's left atrium and left ventricle. It ensures the flow of oxygenated blood from the left atrium to the left ventricle and prevents backflow during ventricular contraction.The tricuspid valve has three leaflets or cusps and is on the right side of the heart. It isbetween the right atrium and the right ventricle, and stops the backflow of blood betweenthe two.

Q69. A single cardiac cycle lasts about:

• A. 0.008 sec
• B. 0.8 sec✓
• C. 8 sec
• D. 0.088 sec

Explanation: The cardiac cycle involves the complete contraction and relaxation of both the atria and ventricles and the cycle lasts for about 0.8 seconds. •Atrial systole, where atria contract and eject blood into ventricles lasts for about 0.1 seconds. •Ventricular systole, where ventricles contract and eject blood lasts for about 0.3 seconds.

Q70. Following the diagram below, identify the portion that is labelled as heavy chain:

• A. 1
• B. 2
• C. 4
• D. 5✓

Explanation: An antibody consists of two heavy chains and two light chains, and two disulfide bridges are present between the two heavy chains and two between the constant region of light chains.

Q71. The induction of immunity by artificially introducing antigens refers to:

• A. Passive immunity
• B. Active immunity
• C. Artificial active immunity✓
• D. Passive active immunity

Explanation: Passive immunity refers to short-term immunity which results from the introduction of antibodies from another person or animal. •Artificial immunity refers to the immunity which refers to the production of antibodies by the immune system in response to the presence of an antigen. •The vaccine is introduced into the body to stimulate the formation of antibodies by the immune system. For example, a polio vaccine is available which helps to provide protection against poliomyelitis. Since over here, antigens are being introduced artificially, it will be considered as artificial active immunity.

Q72. An antibody molecule has a total number of how many polypeptide chains:

• A. 1
• B. 2
• C. 3
• D. 4✓

Explanation: Antibody (or immunoglobulin) molecules are glycoproteins composed of one or more units; each containing four polypeptide chains; two identical heavy(H) and two identical light chains(L) which are connected with each other by disulfide bridge and form a 'Y' shaped structure.

Q73. In case of snake bite venom, passive immunity is produced by antitoxins, so the serum is called:

• A. Antivenom serum✓
• B. Antiserum
• C. Passive immunity serum
• D. Anti snake serum

Explanation: In case of snake bites, the injection that is given to the patients contains preformed antibodies against snake venom. This type of immunization is passive immunization, and this serum is known as antivenom serum. Antivenom serums have been used extensively for over a century and are the only effective treatment option for snake bites and other dangerous animal envenomations.

Q74. The mechanism of regulation, generally between organisms and their environment, of solute and the gain and loss of water is termed as:

• A. Homeostasis
• B. Osmoregulation✓
• C. Thermoregulation
• D. Excretion

Explanation: Option B is correct.•Osmoregulation is a process that regulates the osmotic pressure of fluids and electrolyte balance in organisms. In animals, this process is brought about by osmoreceptors, which can detect changes in osmotic pressure.•Homeostasis is the ability to maintain internal stability in an organism in response to environmental changes. Example: The internal temperature of the human body is the best example of homeostasis. •Thermoregulation is a process that allows your body to maintain its core internal temperature. •Excretion is the process by which organisms expel metabolic waste products and other toxic substances from their body.

Q75. Among the following animals, which ones are endotherms?

• A. Birds✓
• B. Amphibians
• C. Fishes
• D. Both A and C

Explanation: Option A is correct.Endotherms are animals that are dependent on or capable of the internal generation of heat. Birds and mammals are examples of endotherms.

Q76. Blood leaves the Bowman’s capsule by:

• A. Afferent arterioles
• B. Afferent capillaries
• C. Efferent arterioles✓
• D. Efferent capillaries

Explanation: Option C is correct.Blood leaves the Bowman's capsule by Efferent arterioles.The Bowman's capsule is a crucial component of the nephron, the functional unit of the kidney. It plays a role in the initial filtration of blood to form urine. After the glomerulus, which is a network of capillaries within the Bowman's capsule, filters the blood, the filtered fluid (known as the glomerular filtrate) needs to exit the Bowman's capsule and continue through the renal tubules for further processing.

Q77. End-stage renal failure is called:

• A. Kidney failure stage
• B. Hyperoxaluria
• C. Uremia✓
• D. Hypercalcemia

Explanation: Option C is correct.Uremia is the term for high levels of urea in the blood. The uremic syndrome can be defined as the terminal clinical manifestation of kidney failure (also called renal failure), uremia is mostly a consequence of kidney failure. It can be defined as an excess of amino acid and protein metabolism end products, such as urea and creatinine, in the blood that would be normally excreted in the urine.

Q78. Which structure receives about 20% of total blood and has a weight less than 1% of the total body:

• A. Heart
• B. Lungs
• C. Kidney✓
• D. Liver

Explanation: Option C is correct.The kidneys receive approximately 25% of cardiac output or 1250 ml/min via the renal arteries. The high renal blood flow is due to the need for filtration rather than due to metabolic demand.

Q79. The structure which joins a muscle to a bone:

• A. Tendon✓
• B. Ligament
• C. Clavicle
• D. Sternum

Explanation: Tendon is a tough, fibrous, cord-like tissue that connects muscle to bone or another structure, such as an eyeball. Tendons help the bones or structures to move. A ligament is a fibrous connective tissue that attaches bone to bone, and usually serves to hold structures together and keep them stable. The clavicle is involved in the movement of the shoulders and arms, while the sternum provides attachment for ribs.

Q80. Clavicle is present in:

• A. Back bone
• B. Skull
• C. Pelvic girdle
• D. Pectoral girdle✓

Explanation: A pectoral girdle, also referred to as the shoulder girdle, connects your upper limbs to the bones along the axis of your body. The pectoral girdle consists of the two bones that make up your shoulder: the clavicle, or collarbone. scapula, or shoulder blade. The pelvic girdle, or the bony pelvis, is a bony ring, formed by the left and right hip bones and the sacrum, and it surrounds the pelvic cavity and connects the vertebral column to the lower limbs.

Q81. The name of the second vertebrae in the neck region is:

• A. Atlas
• B. Axis✓
• C. Neck vertebra
• D. Floating rib

Explanation: The cervical spine (neck region) consists of seven bones (C1-C7 vertebrae), which are separated from one another by intervertebral discs. Your first vertebra (C1), also called the atlas, is a ring-shaped bone that begins at the base of your skull. It's named the atlas. The second cervical vertebra, or axis, supports the odontoid process.

Q82. Overlapping of thick and thin filaments occurs in:

• A. I band
• B. A band✓
• C. M band
• D. Z band

Explanation: The myosin and actin filaments overlap in peripheral regions of the A band, whereas a middle region (called the H zone) contains only myosin. The I-band is the region on either side of a Z-disc that contains only thin filaments and titin.

Q83. Name the structures which produce response:

• A. Inhibitors
• B. Receptors
• C. Neurons
• D. Effectors✓

Explanation: An effector is a muscle, gland, or cell that performs a specific function in response to a stimulus—for example, A muscle contracts to move an arm.

Q84. A band of axons between two hemispheres is termed as:

• A. Cerebrum
• B. Hemisphere band
• C. Corpus luteum
• D. Corpus Callosum✓

Explanation: The corpus callosum is a large white matter tract that connects the two hemispheres of the brain that ensuring both sides of the brain can communicate and send signals to each other.

Q85. Reflexes of the eyes are received in:

• A. Hypothalamus
• B. Forebrain
• C. Hindbrain
• D. Midbrain✓

Explanation: The midbrain is associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation, acting as a sort of relay station for auditory and visual information.

Q86. The spinal cord is protected by how many layers of meninges:

• A. 2
• B. 3✓
• C. 4
• D. 5

Explanation: The spinal cord is protected by three layers of meninges: dura mater, arachnoid mater, and pia mater.

Q87. Which hormone in the human body is antagonistic to insulin:

• A. Thyroxin
• B. Cortisol✓
• C. Calcitonin
• D. None of these

Explanation: Antagonistic hormones have opposite effects on one another.The hormones antagonistic to insulin are glucagon and cortisol, adrenaline, and growth hormone.Cortisol helps control the body's use of fats, proteins, and carbohydrates; suppresses inflammation; regulates blood pressure; increases blood sugar; and can also decrease bone formation.

Q88. The disease which is caused by the deficiency of thyroxine:

• A. Grave’s disease
• B. Goiter✓
• C. Hyperglycemia
• D. Dwarfism

Explanation: Hyperglycemia is caused by under production of insulin hormone. Option B is correct as iodine deficiency is the most common cause of goiter. The body needs iodine to produce thyroid hormone. If you do not have enough iodine in your diet, the thyroid gets larger to try and capture all the iodine it can, so it can make the right amount of thyroid hormone.

Q89. From among the following, which hormone is the interstitial cell stimulating hormone:

• A. FSH
• B. GH
• C. LH✓
• D. Prolactin

Explanation: Luteinizing hormone (LH), also called interstitial-cell-stimulating hormone (ICSH), is one of two gonadotropic hormones (i.e., hormones concerned with the regulation of the gonads, or sex glands) that is produced by the pituitary gland.

Q90. Failure to produce insulin leads to a condition called:

• A. Diabetes insipidus
• B. Cretinism
• C. Diabetes mellitus✓
• D. Rickets

Explanation: Diabetes occurs when the pancreas, a gland behind the stomach, does not produce enough of the hormone insulin, or the body cannot use insulin properly. Insulin helps carry sugar from the bloodstream into the cells.

Q91. Among the following which hormone is responsible for the suppression of ovulation:

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

Explanation: Progesterone helps to regulate your cycle. But its main job is to get your uterus ready for pregnancy. After you ovulate each month, progesterone helps thicken the lining of the uterus to prepare for a fertilized egg. If there is no fertilized egg, ovulation occurs, progesterone levels drop and menstruation begins.

Q92. The hormone which causes ovulation:

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

Explanation: LH spurs ovulation and helps with the hormone production needed to support pregnancy. Progesterone helps to prepare the body for pregnancy by stimulating glandular development and the development of new blood vessels. FSH helps control the menstrual cycle and the production of eggs by the ovaries. Estrogen regulates the growth, development, and physiology of the human reproductive system.

Q93. Which structure from the following is not present in the male reproductive system:

• A. Urethra
• B. Seminiferous tubules
• C. Vas deferens
• D. Cervix✓

Explanation: The cervix is the lower portion of the uterus, an organ of the female reproductive tract.cervix is a passage that allows fluids to flow inside and out of your uterus. Urethra is the tube through which urine leaves the body. It empties urine from the bladder. The seminiferous tubules are the site of spermatogenesis where germ cells develop into spermatozoa in close interaction with Sertoli cells. The vas deferens is a coiled tube that carries the sperm out of the testes.

Q94. In females, meiosis occurs during which stage:

• A. Spermatogenesis
• B. Gametogenesis✓
• C. Ovulation
• D. None of these

Explanation: Gametogenesis is the production of gametes from haploid precursor cells. Spermatogenesis is a process of developing male gametes, known as sperm within the male reproductive organs, the testes. Ovulation is the process in which a mature egg is released from the ovary.

Q95. Among the following, which one is commonly used as a restriction enzyme:

• A. pBR 101
• B. EcoR1✓
• C. EcoR3
• D. Both pBR 101 and EcoR3

Explanation: EcoRI is a restriction of endonuclease enzymes isolated from species. It is a restriction enzyme that cleaves DNA double helices into fragments at specific sites, and it is also a part of the restriction-modification system. Like all enzymes, a restriction enzyme works shape-to-shape matching. When it comes into contact with a DNA sequence with a shape that matches a part of the enzyme, called the recognition site, it wraps around the DNA and causes a break in both strands of the DNA molecule.

Q96. DNA Polymerase synthesize DNA from _:

• A. RNA
• B. EcoR1
• C. Template RNA
• D. Template DNA✓

Explanation: The main function of DNA polymerase is to synthesize DNA from deoxyribonucleotides, the building blocks of DNA. The DNA copies are created by the pairing of nucleotides to bases present on each strand of the original DNA molecule. During DNA replication, the template is generated by enzymes known as helicases. DNA polymerase then synthesized the DNA using a DNA template.

Q97. DNA polymerase is a temperature-insensitive enzyme extracted from:

• A. Fishelsoni
• B. Thermus aquaticus✓
• C. E. Coli
• D. Both Fishelsoni and Thermus aquaticus

Explanation: Thermus aquaticus is a bacterium that lives in hot springs, and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions like high temperature required during PCR. Therefore is the source of the DNA polymerase used in the PCR technique.

Q98. The method of producing thousands of seedlings is:

• A. PCR
• B. Tissue Culture
• C. Micropropagation✓
• D. Macropropagation

Explanation: Micropropagation is the artificial process of producing plants vegetatively through tissue culture or cell culture techniques. In this artificial process of propagation, plants are produced in vitro by asexual means of reproduction or by vegetative propagation.

Q99. Gene can be made from mRNA using:

• A. PCR
• B. PBr 103
• C. Eco R1
• D. Reverse transcriptase✓

Explanation: The general role of reverse transcriptase is to convert RNA sequences to cDNA sequences that are capable of inserting into different areas of the genome.It is best known for its role in like retroviruses like HIV, where it uses the virus's RNA genome to create DNA, allowing it to integrate into the host's genome. This enzyme has multiple functions, including RNA-dependent DNA polymerase, RNase H (which removes the RNA template), and DNA-dependent DNA polymerase activities. It is also a critical tool in molecular biology.

Q100. The change in frequency of alleles at a locus that occurs by chance is termed as :

• A. Migration
• B. Genetic drift✓
• C. Mutation
• D. Non-random mating

Explanation: Genetic drift is the change in frequency of an existing gene variant in the population due to random chance. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation. Example: Consider a population of rabbits with brown fur and white fur, white fur being the dominant allele. Due to genetic drift, only the brown population might remain, with all the white ones eliminated. Migration is the seasonal movement of animals from one habitat to another in search of food, better conditions, or reproductive needs. Any change in the DNA sequence of a cell is called a mutation. Non-random mating occurs when the probability that two individuals in a population will mate is not the same for all possible combinations of genotypes.

Q101. Organs that are functionally different but structurally alike are termed as:

• A. Vestigial Organs
• B. Comparative embryology organs
• C. Homologous organs✓
• D. None of the given options

Explanation: Homologous organs are referred to as the organs/traits that are inherited by two different organisms but from the same ancestry. Example: The forelimbs of a man, the forelimbs of a cat, the flippers of a whale, and the wings of a bat. Vestigial organs are rudimentary anatomical structures that are retained in a species despite having lost their primary ancestral function. Comparative embryology is the branch of embryology that compares and contrasts embryos of different species, showing how all animals are related.

Q102. The idea of inheritance of acquired characteristics was proposed by:

• A. Darwin
• B. Lamarck✓
• C. Mendel
• D. Wallace

Explanation: Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism, is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It proposes the idea of inheritance of acquired characteristics.

Q103. Succession in previously ecosystem is commonly known as:

• A. Primary succession
• B. Secondary succession✓
• C. Xeric succession
• D. Ancestral succession

Explanation: Secondary succession occurs when the severity of disturbance is insufficient to remove all the existing vegetation and soil from a site. A classic example of secondary succession occurs in oak and hickory forests cleared by wildfire.

Q104. The reason why CO2 is highly stable because it’s _:

• A. Highly stable
• B. Covalent Molecule✓
• C. Highly reactive
• D. Carbon molecule

Explanation: In CO2, carbon, and oxygen first form a double covalent bond. At first, oxygen and carbon share their two valence electrons. This makes a double bond. By doing so oxygen becomes stable. become, carbon, and oxygen first form a double covalent bond. At first, oxygen and carbon share their two valence electrons. This makes a double bond. By doing so oxygenbecomes stable.

Q105. The process of DNA replication in which each strand acts as a template for new double helix, composed of one parental strand and one newly polymerized strand refers:

• A. PCR
• B. Semi-conservative model✓
• C. Conservative mode
• D. Both

Explanation: DNA replication is a semi-conservative process. In this model, the two strands of DNA unwind from each other, and each acts as a template for the synthesis of a new, complementary strand. This results in two DNA molecules with one original strand and one new strand.

Q106. The process in which an RNA copy of the DNA sequence encoding the gene is produced:

• A. Translation
• B. Transcription✓
• C. Polymerization
• D. Genesis

Explanation: Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). DNA safely and stably stores genetic material in the nuclei of cells as a reference or template.

Q107. DNA Polymerase III adds nucleotides to DNA strand, replication always proceeds from:

• A. 3’ → 5’
• B. 5’ → 3✓
• C. Sometime “3’ → 5’ & “5’ → 3’ ”
• D. None of the given options

Explanation: DNA replication occurs in the 5' to 3' direction. DNA polymerase can only add nucleotides the 3' -OH group of the growing DNA strand, this is why DNA replication occurs only in the 5' to 3' direction.

Q108. XO-XX is associated with:

• A. Fishes
• B. Man
• C. Drosophila
• D. Grasshopper✓

Explanation: The XO sex-determination system (sometimes X0 sex-determination system) is a system that some species of insects, arachnids, and mammals use to determine the sex of offspring. In this system, there is only one sex chromosome, referred to as X. Males only have one X chromosome (XO), while females have two (XX). Male grasshoppers have 23 chromosomes and females have 24 chromosomes.

Q109. When an effect caused by a gene or gene pair at one locus interferes with or hides the effect caused by another gene or gene pair at another locus, the phenomenon is called

• A. Bombay phenotype
• B. Codominance
• C. Epistasis✓
• D. Pleiotropy

Explanation: Epistasis is a circumstance where the expression of one gene is modified (e.g., masked, inhibited, or suppressed) by the expression of one or more other genes. Example: A good example of epistasis is coat color in the popular dog breed the Labrador retriever. Labrador retriever coat color genes only come in black or chocolate.

Q110. The phenotype of heterozygote is distinct from those of the two homozygotes, not an intermediate expression, this is termed as:

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

Explanation: Codominance, in genetics, is a phenomenon in which two alleles (different versions of the same gene) are expressed to an equal degree within an organism. As a result, traits associated with each allele are displayed simultaneously. Example: Human blood group AB

Q111. In translation, the termination codon is:

• A. UAA✓
• B. UCG
• C. AUG
• D. UUU

Explanation: Translation is the process by which a cell makes proteins using the genetic information carried in messenger RNA (mRNA). The codons that cause the termination of protein synthesis are known as stop/terminator codons. The DNA stop codons are TAG, TAA, and TGA. The corresponding RNA, stop codons are UAG, UAA, and UGA. AUG is the most common start codon and it codes for amino acid methionine.

Q112. Human female differs from human male in having :

• A. Y chromosome
• B. X chromosome
• C. XY chromosome
• D. XX chromosome✓

Explanation: In humans, sex is determined by the combination of sex chromosomes. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The presence of two X chromosomes is what distinguishes females from males. Option A is incorrect because the Y chromosome is found in males. Option B is incorrect as the X chromosome is present in both sexes. Option C is incorrect as XY is the configuration for males, not females. Therefore, Option D, the XX chromosome pair, correctly identifies the chromosomal difference in females.

Q113. How many essential amino acids are there?

• A. Three
• B. Six
• C. Nine✓
• D. Twelve

Explanation: There are nine essential amino acids. They are essential because they cannot be made by the body. They must be taken from food. Their names are Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Q114. Determine the number of moles of O in 10.6g of Na2CO3:

• A. 0.4 moles
• B. 0.3 moles✓
• C. 0.2 moles
• D. None of the given options

Explanation: 10.6/106 = 0.1 mol 3 oxygen atoms are present so:0.1 x 3 = 0.3 mol Hence, option B is correct.

Q115. Calculate the grams of H2O formed when 8g of CH4 burns in excess of oxygen:

• A. 21 grams
• B. 19 grams
• C. 18 grams✓
• D. 15 grams

Explanation: 8/16 = 0.5 mol of CH4 1 mole of CH4 yields 2 moles of H2O, so 0.5 mole will yield 1 mole of H2O. Mass = mol x Mr = 18 x 1 = 18g Hence, option C is the only right answer.

Q116. Choose the correct option regarding number or particles associated with one mole of a substance:

• A. 6.03 x 1023
• B. 6.01 x 10-19
• C. 6.02 x 10-23
• D. 6.02 x 1023✓

Explanation: One mole of a substance always contains 6.02 x 1023 particles, this is Avogadro's number. (Fact)

Q117. A compound has an empirical formula CH2Cl and molecular formula mass as 99gmol-1, identify the compound:

• A. C2H4Cl
• B. C4H8Cl
• C. C2H4Cl2✓
• D. C2H3Cl3

Explanation: Empirical formula mass = 12 + 2 + 35.5 = 49.5g n = 99/49.5 = 2 2 x (CH2Cl) = C2H4Cl2 Option C is the correct answer

Q118. Identify the value of R at STP:

• A. 8.324 atm dm-3 mol-1
• B. 0.0821 cal K-1 mol-1
• C. 0.0821 atm dm3 K-1 mol-1✓
• D. 8.314 cal K-1 mol-1

Explanation: At STP one mole of a gas occupies 22.4 dm3 and the value of R is 0.0821 atm dm3 K-1 mol-1.

Q119. Which of the following is the most environmentally-friendly source to derive energy?

• A. Lead-acid accumulator
• B. H2- O2 fuel cell✓
• C. Silver Oxide Battery
• D. Alkaline battery

Explanation: The H2-O2 fuel cell is generally considered the more environmentally-friendly energy source. Here's why:Efficiency: H2-O2 fuel cells are more efficient in converting hydrogen and oxygen's chemical energy into electricity than alkaline batteries. Fuel cells can achieve up to 60% conversion efficiency, while alkaline batteries typically have efficiencies below 50%.Renewable Energy Integration: H2-O2 fuel cells can be powered by hydrogen gas derived from renewable sources such as the electrolysis of water using renewable electricity. This means that if the hydrogen is produced from renewable sources, the fuel cell can operate with minimal greenhouse gas emissions. In contrast, alkaline batteries rely on non-renewable resources like zinc, manganese, and nickel, which require mining and extraction processes with associated environmental impacts.Longevity: H2-O2 fuel cells can potentially have a longer lifespan compared to alkaline batteries, which are typically disposable and have a limited useful life. The longer lifespan of fuel cells reduces waste generation and the need for frequent replacements.Recycling: While both H2-O2 fuel cells and alkaline batteries can be recycled, the recycling infrastructure for fuel cells is more developed. Fuel cell components, such as the catalysts, can be reused or recycled, whereas alkaline batteries often end up in landfill due to limited recycling facilities. Proper recycling of fuel cells reduces the environmental impact and promotes the recovery of valuable materials.

Q120. What is the reason that ice at 0˚ occupies more volume than water:

• A. Empty spaces✓
• B. Ionic bond
• C. Intermolecular
• D. Debye forces

Explanation: When water freezes, water molecules arrange into a crystal structure. It happens that, unlike most crystals, this one happens to have an arrangement that takes up a little more room than the liquid because of empty spaces.

Q121. The shape of s-orbital is _ and the shape of p-orbital is _.

• A. Spherical, dumb-bell✓
• B. Dumb-bell, spherical
• C. Spherical, double dumb-bell
• D. Spherical, spherical

Explanation: The s-orbital is spherical and the p-orbital is dumb-bell shaped.Hence, the correct option is A

Q122. Pi-bond is formed by sideways overlap of _?

• A. s-orbitals
• B. p-orbitals✓
• C. d-orbitals
• D. None of the given options

Explanation: The π bond is formed by the side-by-side overlap of the two unhybridized p orbitals in the two carbon atoms. The two lobes of the π bond are above and below the plane of the σ system.

Q123. What is the exact value of angle in BF3:

• A. 90˚
• B. 119.5˚
• C. 104.5˚
• D. 120˚✓

Explanation: There are no lone pairs in the central atom B. Since the central atom has 3 peripheral atoms (3 F atoms) and no lone pairs, it will exhibit a trigonal planar geometry. The trigonal planar geometry has a bond angle of 120 degrees. Therefore, the molecule will have a bond angle of 120 degrees.

Q124. Determine the value of Enthalpy of formation of NH4Cl.

• A. - 788 kJmol-1
• B. -314.55 kJmol-1✓
• C. -692 kJmol-1
• D. None of the given options

Explanation: The enthalpy formation of NH4Cl is experimentally found out to be -314.55 kJ/mol

Q125. Enthalpy is measured at _:

• A. 300 K and 2 atm
• B. 300 K and 1atm
• C. 298 K and 1 atm✓
• D. 295 K and 1 atm

Explanation: Enthalpy is measured at standard conditions i.e. 298 K and 1 atm.

Q126. During space flights, astronauts obtain water from _:

• A. Nickel cadmium cells
• B. Fuel cells✓
• C. Lead accumulator
• D. Alkaline battery

Explanation: Fuel cells directly convert the chemical energy in hydrogen to electricity, with pure water and potentially useful heat as the only byproducts.

Q127. For the purification, impure copper is made the:

• A. Cathode
• B. Anode✓
• C. Solution
• D. Both Cathode and Anode

Explanation: In the electrolysis process for purifying copper, the impure copper is used as the anode. When an electric current is passed through the solution, copper atoms from the anode dissolve into the solution as copper ions (Cu2+) and migrate to the cathode, where they gain electrons and deposit as pure copper. The impurities in the anode either fall off or remain in the solution, depending on their solubility. The cathode, made of pure copper, is the site of copper deposition.Option A is incorrect because the cathode is not made of impure copper; it serves as the site for deposition of pure copper. Option C is incorrect as the solution is part of the electrolysis setup but does not refer to the impure copper. Option D is incorrect as it suggests both electrodes are made of impure copper, which is not the case.

Q128. Ca(OH)2 is sparingly soluble having solubility constant value 6.5 x 10-6. What’ll be its solubility:

• A. 2.75 x 10-2
• B. 2.75 x 102
• C. 1.17 x 10-2✓
• D. 3.63 x 103

Explanation: The solubility product constant (Ksp) expression for Ca(OH)2is: Ca(OH)2(s) ⇌ Ca2+(aq) + 2OH-(aq) The Ksp expression can be written as: Ksp = [Ca2+][OH-]^2 Given that the solubility constant value (Ksp) is 6.5 x10^-6, we can assume that x mol/L of Ca(OH)2 dissolves, leading to theformation of x mol/L of Ca2+ and 2x mol/L of OH-. Substituting these values into the Ksp expression, we get: 6.5 x 10^-6 = (x)(2x)^2 6.5 x 10^-6 = 4x^3 Dividing both sides by 4, we have: 1.625 x 10^-6 = x^3 To find x, we can take the cube root of both sides: x = (1.625 x 10^-6)^(1/3) Calculating this value gives us: x ≈ 0.0117 mol/L Therefore, the solubility of Ca(OH)2 is approximately 0.0117mol/L.

Q129. Units of k in first order reaction are:

• A. s-1✓
• B. moles dm-3 s-1
• C. moles dm-3
• D. mol-1 dm3

Explanation: k= rate / [concentration of reactant] k in units is = mol. dm-3 . s-1 / mol. dm-3 So the units of k are s-1.

Q130. Rate of first order reaction depends on:

• A. Concentration of one reactant✓
• B. Concentration of two reactants
• C. Concentration of three reactants
• D. Independence of the initial concentration

Explanation: In a first-order reaction, the rate depends on the concentration of one reactant. This means that the rate of the reaction is directly proportional to the concentration of that particular reactant. The rate law for a first-order reaction is typically written as Rate = k[A], where [A] represents the concentration of the reactant 'A.' So, this option is correct.

Q131. Among the following, which contains the same no. of electrons & protons but different no. of neutrons:

• A. Isboars
• B. Isotopes✓
• C. Isotones
• D. None of the given options

Explanation: Isotopes are atoms of the same element with same proton and electron numbers but different numbers of neutrons.

Q132. Melting point of Na & Mg decreases down the group due to:

• A. Strong electronegativity
• B. Strong attractive forces
• C. Increment in size✓
• D. High Ionization Energy

Explanation: Generally the melting point of the metals decreases down the group. This is because as the metal ions get larger the distance between the bonding electrons and the positive nucleus gets larger and reduces the overall attraction between the two.

Q133. Ionic radius decreases along the period due to:

• A. Addition of a new shell
• B. Increase in nuclear charge✓
• C. High Ionization Energy
• D. Decrease in nuclear charge

Explanation: Across a period, effective nuclear charge increases as electron shielding remains constant. A higher effective nuclear charge causes greater attraction to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius.

Q134. Identify the element that has maximum oxidation states:

• A. Zinc
• B. Chromium
• C. Vanadium
• D. Manganese✓

Explanation: Common oxidation states of manganese are +2, +3, +4, +6, and +7, although all oxidation states from −3 to +7 have been observed.

Q135. How many ligands does K4[Fe(CN)6] contains:

• A. 4
• B. 7
• C. 6✓
• D. 5

Explanation: In the given complex six cyanide ligands are bonded to the central atom, iron.

Q136. To avoid the oxidation of filaments which element is used in electric bulbs:

• A. Krypton
• B. Argon✓
• C. Helium
• D. Neon

Explanation: Argon gas is an inert gas used in electric bulbs to prevent corrosion of its tungsten filament. Since it doesn't react with tungsten, it stops the filament from burning away in the presence of oxygen. Hence, increases the bulb's life.

Q137. Among the following, which compound is a catalyst in contact process:

• A. V2O5✓
• B. H2SO4
• C. NH4Cl
• D. NaOH

Explanation: The catalyst used in contact process is always vanadium pentaoxide i.e V2O5 .

Q138. In contact process, optimum temperature lies between _:

• A. 200-300˚C
• B. 300-400˚C
• C. 400-500˚C✓
• D. 300-500˚C

Explanation: A temperature of 450oC is used in this reaction. This is because the reaction is exothermic such that a low temperature would favor the forward reaction and produce more sulfur trioxide. However, a low temperature slows down the rate of the reaction. Thus a compromise temperature of 450oC is used.

Q139. Nitrogen is required by plants for the _:

• A. Formation of starch and sugar
• B. Development of roots and leaves✓
• C. Stimulation of early growth
• D. Formation of fruit

Explanation: Nitrogen is an essential macronutrient for plant function and is a key component of amino acids, which form the building blocks of plant proteins and enzymes. Proteins make up the structural materials of all living matters and enzymes facilitate the vast array of biochemical reactions within a plant.

Q140. Name the compound, which shows geometric isomerism:

• A. 1-bromo-2-chloropropene
• B. 2-pentene
• C. 2,3-dimethyl propene
• D. Both “1-bromo-2 chloropropene” & “2-pentene”✓

Explanation: 1-Bromo-2-chloropropene exhibits geometric isomers because each of the bonding atoms of C=C double bond is bonded to two different groups or atoms (one bonded to -Cl and -CH₃, and one bonded to -H and -Br). 2-pentene also exhibits geometric isomers because each of the bonding atoms of the C=C double bond is bonded to two different groups or atoms (one bonded to -H and -CH₂CH₃, and one bonded to -H and -CH₃). So, the correct answer is D) Both “1-bromo-2 chloropropene” & “2-pentene”.

Q141. Cyclobutane structure is categorized under:

• A. Aromatic compounds
• B. Alicyclic compounds✓
• C. Aliphatic compound
• D. Heterocyclic compounds

Explanation: The cyclobutane structure is categorized under alicyclic compounds. Alicyclic compounds are a type of organic compounds that contain one or more carbon rings that are saturated, meaning they consist only of single carbon-carbon bonds. These rings can be either cycloalkanes or cycloalkenes.

Q142. What should be the temperature and pressure respectively for catalytic cracking:

• A. 500˚C, 2 atm✓
• B. 900˚C, 2 atm
• C. 500˚C, 4 atm
• D. 900˚C, 4 atm

Explanation: 500oC and 2 atm are the fixed conditions for catalytic cracking. (Fact)

Q143. At 25˚C with phenol 2-4-Dinitrophenol is formed by the reaction of:

• A. (HNO3 + H2SO4) with benzene
• B. (HNO3 + H2SO4) with phenol✓
• C. NaOH with Benzene sulphonic acid
• D. Sodium phenotype with HCl

Explanation: Phenol reacts with (HNO3 + H2SO4) to form nitrophenol. Phenols are 2,4 activating thus the compound formed is named “2,4- dinitrophenol” Reference: 12-chemistry-cbse-5f7c7f85bc84ec3b223f3bb5

Q144. For halogenation of benzene, which reagent is used:

• A. H2SO4
• B. AlCl3✓
• C. HNO3
• D. HCl

Explanation: In the halogenation of benzene, AlCl3 is used as a catalyst to make the halogen into a strong electrophile. This allows the halogen to attack the electron cloud on the benzene ring and react with it. The correct answer is AlCl3. Options A, C, and D are incorrect because they do not facilitate the formation of a strong electrophile needed for the reaction to occur.

Q145. Among the following, which one has an electron withdrawing effect:

• A. -NH2
• B. -N(CH3)2
• C. -CHO✓
• D. -I

Explanation: Aldehydes are electron withdrawing because they tend to withdraw electrons from electron-rich systems. The reason is because of the presence of a more electronegative atom in its carbonyl structure which in turn leads to the development of an inductive effect. All the other groups are electron donating.

Q146. Catalytic oxidation of alkanes results in the formation of _:

• A. Carboxylic acid
• B. Aldehyde
• C. Ketone
• D. Alcohol✓

Explanation: Catalytic oxidation of alkanes always results in the formation of alcohols. Alcohols are either formed as an intermediate or as a final product. Option D is correct because alcohols are the primary product of this reaction. Options A, B, and C are incorrect because while aldehydes, ketones, and carboxylic acids can be formed from further oxidation of alcohols, the direct product of catalytic oxidation of alkanes is alcohol.

Q147. Which of the following is an intermediate compound in SN1:

• A. Ethoxide ion
• B. Alkyl halide
• C. Alkene
• D. Carbocation✓

Explanation: The product of step 1, carbocation, will be the reactant of the next step and is called the intermediate for the SN1 reaction. Intermediate is the unstable, highly-reactive specie with a very short lifetime. The carbocation intermediate is in trigonal planar shape, with the empty 2p orbital particular to the plane.

Q148. Among the alkyl halides, which always follows SN2 mechanism:

• A. Primary alkyl halides✓
• B. Secondary alkyl halides
• C. Tertiary alkyl halides
• D. Both secondary and tertiary alkyl halides

Explanation: Since primary alkyl halide is least sterically hindered among primary, secondary and tertiary alkyl halides therefore primary alkyl halides undergo SN2 reaction.

Q149. Among the following, which one is a nucleophile;

• A. H+
• B. OH-✓
• C. Ca2+
• D. None of the given options

Explanation: Nucleophile is a word used to refer to substances that tend to donate electron pairs to electrophiles in order to form chemical bonds with them. Any ion or molecule having an electron pair that is free or a pi bond containing two electrons has the ability to behave like nucleophiles. Here, OH has a negative charge meaning it can donate electrons.

Q150. In elimination reactions, _ is used:

• A. Acidic K2Cr2O7
• B. CuCl
• C. Acidic NaOH
• D. Alcoholic KOH✓

Explanation: The reagent used in the Elimination reaction (𝛃 – elimination) in case of alkyl halides is alcoholic KOH.

Q151. Identify the product X in the following reaction:CH3COOH + PCl5 → X + POCl3 + HCl

• A. CH3COCl✓
• B. CH3COCl2
• C. CH3COCH2Cl2
• D. CH2COCl2

Explanation: Here’s the reaction mechanism. In the given reaction: CH3COOH + PCl5 → X + POCl3 + HCl The product X is acetyl chloride (CH3COCl).

Q152. Reaction of alcohol with hydrogen chloride yields:

• A. Alkyl halide✓
• B. Carboxylic acid
• C. Aldehyde
• D. Ester

Explanation: The following is the chemical equation of the reaction. ROH + HCl → RCl + H2O In this reaction, the hydroxyl group (-OH) of the alcohol (ROH) is replaced by a chlorine atom (-Cl) from the hydrogen chloride, resulting in the formation of an alkyl chloride (RCl). Simultaneously, water (H2O) is generated as a byproduct.

Q153. The acidity of Phenol is due to its _:

• A. Nature of Benzene
• B. Double bond in benzene ring
• C. Nature of phenoxide✓
• D. Hydroxyl group

Explanation: The acidity of phenols is due to their ability to lose hydrogen ions to form phenoxide ions. In a phenol molecule, the sp2 hybridized carbon atom of the benzene ring attached directly to the hydroxyl group acts as an electron-withdrawing group.

Q154. Sodium phenoxide on treating with hydrochloric acids yields:

• A. Benzene
• B. Benzoic acid
• C. Phenol✓
• D. Benzaldehyde

Explanation: Here’s the following equation. C6H5ONa + HCl → C6H5OH + NaCl In this reaction, sodium phenoxide (C6H5ONa) reacts with hydrochloric acid (HCl) to yield phenol (C6H5OH) and sodium chloride (NaCl). The sodium phenoxide is protonated by the hydrochloric acid, resulting in the formation of phenol and sodium chloride as the salt byproduct.

Q155. Which reagent is responsible for the conversion of ketone to secondary alcohol:

• A. NaAlH4
• B. NaBH4✓
• C. Al
• D. Red Phosphorus

Explanation: Aldehydes and ketones are usually reduced by sodium borohydride or lithium aluminum hydride to alcohols.

Q156. Both aldehyde and ketones give _:

• A. Tollen’s test
• B. 2,4-DNPH test✓
• C. Benedict’s solution test
• D. Sodium nitroprusside test

Explanation: An aqueous solution of 2,4-dinitrophenyl hydrazine (DNP) is known as Brady's reagent. It reacts with carbonyl compounds (aldehydes and ketone) to give an orange coloured precipitate.

Q157. To distinguish aldehyde from ketone which solution is used:

• A. Alkaline solution
• B. Fehling's solution✓
• C. A solution containing K2Cr2O7
• D. A solution containing acid only

Explanation: To distinguish between an aldehyde and a ketone, we can use Fehling solution. Fehling solution is a mixture of two solutions: Fehling solution A, which contains copper sulfate, and Fehling solution B, which contains sodium hydroxide and potassium tartrate. When we add Fehling solution to a solution containing an aldehyde, like formaldehyde or acetaldehyde, a red precipitate of copper(I) oxide is formed. However, if we add Fehling solution to a solution containing a ketone, like acetone or propanone, no reaction occurs. So, by using Fehling solution, we can differentiate between aldehydes and ketones.

Q158. Identify the compound, which gives positive iodoform test:

• A. Methanol
• B. Methyl ketone✓
• C. 3-Hexanol
• D. Propionaldehyde

Explanation: When a methyl ketone is halogenated in a basic solution, the halogen replaces all three α-hydrogen atoms. This trihalomethane reacts further, resulting in the cleavage of a carbon–carbon bond. After acidification, the products are carboxylic acid and trihalomethane known as a haloform.

Q159. Which of the following is the functional group for carboxylic acids?

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

Explanation: The carboxyl functional group that characterizes the carboxylic acids is unusual in that it is composed of two functional groups: (1) the carboxyl group and (2) a hydroxyl group bonded to a carbonyl group. It is often written in condensed form as –CO2H or –COOH.

Q160. Final product of hydrolysis of nitrile yield:

• A. Ketone
• B. Ketone
• C. Alcohol
• D. Carboxylic acid✓

Explanation: Nitriles can be hydrolyzed to carboxylic acids in acidic aqueous solutions.

Q161. During esterification, the bond from alcohol that breaks in between:

• A. Carbon and oxygen
• B. Oxygen and hydrogen✓
• C. Carbon and carbon
• D. None of the given options

Explanation: Only the OH part breaks.During esterification, the bond that breaks in the alcohol molecule is the O-H bond. This bond is cleaved, and the hydroxyl group (-OH) from the alcohol combines with a carboxylic acid, leading to the formation of an ester and water as a byproduct.The reaction can be represented as:Alcohol + Carboxylic Acid ⇌ Ester + WaterFor example, the esterification reaction between ethanol (alcohol) and acetic acid (carboxylic acid) can be written as:CH3CH2OH + CH3COOH ⇌ CH3COOCH2CH3 + H2OIn this reaction, the O-H bond in the ethanol moleculebreaks and the hydroxyl group (-OH) combines with the carboxylic acid group(-COOH) from acetic acid to form ethyl acetate (ester). Water is released as athe byproduct of this esterification reaction.

Q162. 2-propanoate on oxidation gives:

• A. Aldehyde
• B. Ketone✓
• C. Carboxylic acid
• D. Alcohol

Explanation: 2-propanoate means the ion or ester derived from 2-propanol (isopropanol)Because in 2-propanol (CH₃–CHOH–CH₃), the –OH group is attached to a middle carbon (secondary alcohol).When a secondary alcohol is oxidized, it loses hydrogen from that carbon and oxygen is added — forming a carbonyl group (C=O).That makes it a ketone (CH₃–CO–CH₃, acetone).Rule:Primary alcohol → Aldehyde → AcidSecondary alcohol → KetoneTertiary alcohol → No oxidation easily

Q163. Chloroform is used as the following except:

• A. Precursor of making Teflon✓
• B. Precursor of making refrigerants
• C. Anesthetic
• D. Embalming chemicals

Explanation: Chloroform is used as an anaesthetic, in embalming chemicals, and as a precursor for some refrigerants. Teflon is made from tetrafluoroethylene, not chloroform, Therefore. chloroform is not used in the production of Teflon.

Q164. What do you call the process when sodium periodate is reacted to 1,2-diols?

• A. Protonation
• B. Epoxidification
• C. Oxidative cleavage✓
• D. Esterification

Explanation: 1,2-Diols can be cleaved oxidatively with sodium periodate NaIO4 (and lead tetraacetate) to form two carbonyl compounds in this case formaldehyde, and periodic acid. The process of reacting sodium periodate (NaIO4) with 1,2-diols is known as periodate cleavage or periodate oxidation. It is a chemical reaction that specifically cleaves the carbon-carbon (C-C) bond at the 1,2 position (vicinal position) of diols.

Q165. Identify the monomers of Polyvinyl chloride:

• A. Vinyl acetate
• B. Butyl maleate
• C. Styrene
• D. Vinyl chloride✓

Explanation: Polymer is made of repeat units of the monomer vinyl chloride

Q166. Among the following, which compound is formed by addition polymerization:

• A. Polystyrene✓
• B. Polyester
• C. Nylon
• D. Both Polystyrene & Polyester

Explanation: Repeat units of styrene are added to each other to form the polymer polystyrene whereas polyester and nylon are condensation polymers.

Q167. Phosphoprotein comes under the type of which proteins:

• A. Simple protein
• B. Conjugated protein✓
• C. Derived protein
• D. Both Conjugated & Derived protein

Explanation: Phosphoproteins are conjugate proteins, post-translationally modified by the attachment of phosphate groups.

Q168. Which agent is responsible for acid rain:

• A. O2
• B. Ca(SO4)
• C. NO2
• D. HNO3 and H2SO4✓

Explanation: HNO3 and H2SO4 are acidic compounds which dissolve in rain water to form acid rain

Q169. Chlorination and Bromination mostly uses:

• A. Radio waves
• B. Visible light
• C. Infrared radiations
• D. U.V. light✓

Explanation: The free-radical substitution reaction consists of three steps: In the initiation step, the halogen bond (Cl-Cl or Br-Br) is broken by UV energy to form two radicals. These radicals create further radicals in a chain-type reaction called the propagation step.

Q170. Dehydration of methyl alcohol with concentrated sulphuric acid gives:

• A. CH3CHO
• B. C2H4
• C. HCHO
• D. None of these✓

Explanation: This reaction yields dimethyl ether so the correct answer is none of these. The dehydration of methyl alcohol (methanol) with concentrated sulfuric acid (H2SO4) results in the formation of dimethyl ether. The reaction can be represented as: 2CH3OH + H2SO4 → (CH3)2O + H2O In this reaction, methanol (CH3OH) reacts with concentrated sulfuric acid, which acts as a dehydrating agent. The reaction proceeds by removing a water molecule (H2O) from two molecules of methanol, leading to the formation of dimethyl ether ((CH3)2O) as the product.

Q171. How many pi bond(s) are there in ethene?

• A. None
• B. One✓
• C. Two
• D. Three

Explanation: Ethene has a double bond between two carbon atoms. One sigma bond and one pi bond. Each carbon has two sigma bonds with two hydrogen atoms as carbon valency is four. So, Ethene has 5 sigma bonds and 1 pi bond.

Q172. Diffraction is the characteristic of:

• A. Particle nature of light
• B. Wave nature of light✓
• C. Dual nature of light
• D. None of the above

Explanation: When light behaves like electromagnetic radiation and travels in a straight line it shows the wave nature of light. Young’s double slit experiment proves the wave nature of light. Diffraction, reflection, refraction, polarization, and interference of light are characteristics of the wave nature of light.

Q173. A source of sound having a frequency “f” is moving with the velocity “u” towards a stationary listener. If “v’’ is the velocity of the sound, then the apparent frequency of the sound heard by the observer would be:

• A. vf / (v + u)
• B. (v +u/v)f
• C. vf/(v-u)✓
• D. (v - u/v)f

Explanation: Doppler effect formula is= F0 = (v+v0/v +u) f f0= observed frequency v=velocity of sound in air (330m/s) u= velocity of the source v0= velocity of the observer the observer’s velocity is zero, so V0 is equal to zero. Substituting this into the Doppler effect equation above, we get the equation of the Doppler effect when a source is moving towards an observer at rest. Now if we rearrange the equation according to our case; Then F0= vf/v-u The sign is negative when the source moves toward the stationary observer and positive when the source moves away from the observer.

Q174. When resistances are connected in series, the equivalent resistances is equal to:

• A. Product of the reciprocals of the individual resistances
• B. Sum of the reciprocals of the individual resistances
• C. Product of the individual resistances
• D. Sum of the individual resistances✓

Explanation: Resistors are said to be in series when equal current flows through each resistor because there is only one path for the charges to flow through. The equivalent resistance of a set of resistors in a series connection is equal to the algebraic sum of each individual resistance. Since the current is constant and the voltage is equal to the potential energy per charge, the sum of the voltage applied to the circuit by the source and the potential drops across the individual resistors around a loop should be equal to zero according to Kirchoff’s loop law. V=V1- V2-V3 = 0 = V = V1+V2+V3 = V = IR1+ IR2+IR3 = I = v/ R1+ R2+R3 = V/Req Hence If n resistors are connected in series, the equivalent resistance is given by: Req = R1+R2+R3+Rn B. When resistances are connected in parallel, the equivalent resistance is equal to the sum of the reciprocal of individual resistances. As the voltage across each resistor remains constant and the current splits across each resistor according to Kirchoff’s junction rule. Hence the equivalent resistance in this case is the sum of the reciprocal of individual resistances. I = I1+I2 =V1/R1 + V2/R2 = V/R1 + V/R2 = V ( 1/R1+ 1/R2) = V/Req =1/Req = (1/R1+ 1/R2)

Q175. A wire of resistance 4Ω is bent in the form of a circle. The resistance between the ends of any diameter is:

• A. 1 Ω✓
• B. 2 Ω
• C. 4 Ω
• D. 8 Ω

Explanation: In forming a ring and measuring the resistance across the diameter, we divided the length of the wire in half. If the whole wire before we bent it is 4 ohms, then each half considered by itself is 2 ohms.What this then means is that we’ve reduced this to two 2-ohm resistances in parallel.According to the formula for resistances in parallel:1/R AB = 1/R1 + 1/R2 = 2/2R = 1/ROrRAB = 1 ohm is our answer.

Q176. Which of the following is a supplementary physical quantity?

• A. Radian
• B. Steradian
• C. Both Radian & Steradian✓
• D. None of the given options

Explanation: Supplementary quantities are quantities of a circle and a sphere. Supplementary units are those that aren't yet graded as either base or derive. Plane angle and solid angle are two supplementary units of two purely" geometrical physical quantities. and their units are radian (rad) and steradian (Sr) respectively.

Q177. In YDSE, if we use white light in place of monochromatic light, then the:

• A. Centre will be bright and red color will be far from it✓
• B. Centre will be bright and blue color will be far from it.
• C. Centre will be dark and red color will be to it
• D. Centre will be dark and blue color will be to it

Explanation: When we use white light in place of monochromatic light then only the central fringe looks white and other fringes of different colors are observed. The difference in path lengths, being zero at the center gives zero phase difference at the center for all wavelengths hence making the center fringe white. It is because the central fringe for all colors is formed at the center point so it becomes white after mixing up. As fringes of other colors fall at different places we see fringes of all colors on the central bright fringe. At other different points on the screen, the phase difference is given by ϕ=kΔx=2π/​λΔx where Δx is the difference in path lengths. Since λ is different for different colors, the fringe width will be different for each color and hence all other fringes will be colored. The red color will be observed further away from it because it has a shorter wavelength.

Q178. The vertical extension in a light spring by a weight of 1 kg suspended from the wire is 9.8 cm, the period of the oscillation is:

• A. 20𝜋/sec
• B. 2𝜋/sec
• C. 2𝜋/10 sec✓
• D. 200𝜋/sec

Explanation: Following is the correct solution:

Q179. The velocity and acceleration of a particle performing S.H.M. have a steady phase relationship. The acceleration showed a phase lead over the the velocity of:

• A. π
• B. π/2✓
• C. -π/2
• D. -π

Explanation: In simple harmonic motion (S.H.M.), the displacement x is given by x = a sin(ωt). The velocity v, being the first derivative of displacement with respect to time, is v = aω cos(ωt). The acceleration a, the derivative of velocity, is given by a = -aω^2 sin(ωt), which can also be expressed as a = aω^2 cos(ωt + π/2). This shows that acceleration leads velocity by a phase of π/2 radians. The other options are incorrect because they represent different or opposite phase relationships that do not apply to the phase relationship between velocity and acceleration in S.H.M.

Q180. Laser beam can be used to generate three-dimensional images of objects in a process called:

• A. Tomography
• B. Holography✓
• C. Electrography
• D. Xerography

Explanation: Holography is a technique that uses laser and photographic plates to produce three-dimensional images of objects on film by encoding not just the intensity but also the phase information of the light striking the film.

Q181. During adiabatic compression work done is equal to 200 J. What will be the change in internal energy?

• A. -200 J
• B. +200 J✓
• C. 100 J
• D. 0 J

Explanation: In an adiabatic system no heat exchange between the system and surrounding. In adiabatic compression work done by the system is negative so the change in internal energy will be positive. Or -W=U Since work done by the system is -200 J The change in internal energy will be +200 J

Q182. If heat energy of 100 J is taken out but 400 J work is done on the system, the change in internal energy is:

• A. -300 J
• B. 300 J✓
• C. -100 J
• D. 0 J

Explanation: ΔQ=ΔW+ΔU100 J =400 J+ΔU100 J - 400 J= ΔUΔU=300 J

Q183. A conductor of length 1m carrying current of 1A is placed parallel to a magnetic field of 1 Gauss. The magnetic force acting on the conductor is:

• A. Zero✓
• B. 1 Newton
• C. 10-4 Newton
• D. 1 dyne

Explanation: The formula of Magnetic force is F=BIL sinθ F=1x 1 x 1 x 0 = 0 Since the wire is placed parallel to the magnetic field, No force acts on the conductor. Sin 0 = 0 If the wire was placed perpendicular to the magnetic field then sin 90= 1 and the answer would be 1 Newton. F=BIL sinθ F= 1 x 1 x 1 x 1 = 1 Newton Dyne is also a unit of force in the CGS system. 1 Dyne= 10-4 Newton

Q184. The hardest photon coming out from a Coolidge tube belongs to:

• A. Characteristic X-Rays✓
• B. Continuous X-Rays
• C. Characteristic & Continuous X-Rays
• D. None of the options given

Explanation: Characteristic X-rays are a unique property of individual elements.A high-energy electron knocks out an already existing electron in one of the shells of an anode atom, thus creating a vacancy in that particular shell of the atom. This event energizes the atom and an electron from a higher shell jumps to fill the vacancy in the lower shell so that the overall energy of the atom is decreased. This decrease in energy gives birth to the X-ray photon. So, characteristic X-ray photons are consequences of energy level transitions in the anode atoms. Continuous X-rays are created when free-moving electrons electromagnetically interact with nuclei. Continuous X-rays come from bremsstrahlung ( braking radiation) as the high-energy electrons approach the nucleus of a heavy metal. Since the electron could come very close to the nucleus (and give up a lot of energy to the production of an X-ray photon) or pass far from the nucleus (and give up relatively little energy), the range of the photon energies will be less and continuous.

Q185. Which of the following X-rays has the largest intensity?

• A. Kα X-Ray✓
• B. Kß X-Ray
• C. Kγ X-Ray
• D. All of these options have the same intensity

Explanation: Kα X-rays exhibit the largest intensity due to the considerable energy released when an electron transitions from the n=2 to n=1 energy level in an atom. This transition generates a strong ionization effect, allowing Kα X-rays to ionize a greater number of atoms in a short distance, resulting in their higher intensity. In contrast, Kß X-rays, while having greater penetration power, possess lower ionization and intensity. Kγ X-rays, although they penetrate effectively, also do not have the same ionization capability, making them less intense than Kα X-rays. The fourth option incorrectly assumes equal intensity across all types, which is not the case.

Q186. The half-life of radium is about 1600 years. If 100 g radium exists now, 25 g will remain undecayed after:

• A. 4800 years
• B. 6400 years
• C. 2400 years
• D. 3200 years✓

Explanation: According to the formula:N=N0(½)nN0 = Initial amountN= Remaining amountn= number of half-livesN=N0(½)n = N/N0=(½)n=25/100=(½)nn=2To reduce 100g to 25g, it will take 2 half-lives.Half-life of radium =1600Time taken=2x1600=3200 years

Q187. Pressure of a gas is directly proportional to:

• A. Average K.E. of its molecules
• B. Average vibrational K.E. of its molecules
• C. Average translational K.E. of its molecules✓
• D. All of the above

Explanation: The pressure of a gas is directly proportional to the average translational kinetic energy (K.E.) of its molecules.This is based on the kinetic molecular theory of gases, which states that:1. Gas molecules are in constant random motion.2. The molecules collide with each other and the container walls.3. The collisions with the walls cause the pressure exerted by the gas.The average translational kinetic energy of the molecules is directly related to the temperature of the gas. As the temperature increases, the molecules move faster and have more kinetic energy.The pressure (P) of a gas is directly proportional to the average translational kinetic energy (K.E.) of its molecules, which can be expressed mathematically as:P ∝ K.E.orP = (2/3) × (K.E.) × (density of the gas)This means that if the average translational kinetic energy of the molecules increases, the pressure of the gas also increases.This relationship is a fundamental principle in the behavior of gases and is a key concept in understanding the properties of gases.

Q188. A resistor of 6 Ω with a tolerance of 10% and another of 4 Ω with a tolerance of 10% are connected in series. The tolerance of combination is about:

• A. 5%
• B. 12%
• C. 10%✓
• D. 13%

Explanation: the resistances are R1=6Ω and R2=4Ω. Tolerance in the resistances: ΔR1=.6Ω ΔR2 =.4Ω The total resistance of the combination Req=R1+R2=6+4=10Ω Total tolerance in the equivalent resistance:ΔReq=ΔR1+ΔR2=.6+.4=1Ω Hence percentage tolerance of combination = 1Ω/10Ω × 100= 10 %

Q189. The value of ratio off displacement to distance is:

• A. Always more than one
• B. Always less than one
• C. Equal or more than one
• D. Equal or less than one✓

Explanation: Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion and Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position. It is independent of the path and only depends on the initial and final point. Displacement is equal to or less than distance, it can never be more than distance, Hence The ratio of displacement to distance can be equal to or less than one but never more than one.

Q190. The ratio of shear stress and shear strain is called:

• A. Young’s Modulus✓
• B. New Modulus
• C. Bulk Modulus
• D. Compressive Modulus

Explanation: Young's modulus (E) is a property of the material that tells us how easily it can stretch and deform and is defined as the ratio of tensile stress (σ) to tensile strain (ε). The ratio of shearing stress to the corresponding shearing strain is known as shear modulus, Young’s modulus, or modulus of rigidity.

Q191. Angular speed of minutes hand of mechanical watch is:

• A. π/30 rad/sec
• B. π rad/min
• C. π/2 rad/min
• D. None of the Above✓

Explanation: Time taken by minute hand to rotate by 2𝞹 radians(in a complete cycle) = t= 1 hour = 60 minutes= 3600s w= 𝞱/t = 2𝞹/t =2𝞹/3600 = 𝞹/1800 rad/s is the correct answer. If we do it by minutes instead of seconds then: w= 𝞱/t = 2𝞹/t =2𝞹/60 = 𝞹/30 rad/min Because we used minutes so the units need to be rad/min and not rad/sec

Q192. A force F is applied to a beam at a distance d from a pivot. The force acts at an angle ø to a line perpendicular to the beam.Which combination will cause the largest turning effect about the pivot?

• A. F=Large d=Large ø=Large
• B. F=Large d=Large ø=Small✓
• C. F=Small d=Small ø=Large
• D. F=Small d=Large ø=Small

Explanation: The turning effect of a force is known as the moment. It is the product of the force multiplied by the perpendicular distance from the line of action of the force to the pivot or point where the object will turn moment = fdsin𝞱 According to the formula; for the moment/turning effect to be larger the force and distance should be large and the angle between them should be close to 90(sin=perpendicular) which is small. If the angle is large/greater than 90 then the turning effect would decrease. If force and distance are small, the turning effect would also decrease.

Q193. A body is moving in a circular path with constant speed. Which combination will cause the largest turning effect about the pivot?

• A. Tangential= rv2 Centripetal=0
• B. Tangential=0 Centripetal=0
• C. Tangential=0 Centripetal=v2/r✓
• D. Tangential=v2/r Centripetal=v2/r

Explanation: When an object moves in a circle, it has a centripetal acceleration, directed toward the center. The centripetal acceleration is due to the change in the direction of tangential velocity, whereas the tangential acceleration is due to any change in the magnitude of the tangential velocity. If the speed is not constant, then there is also a tangential acceleration. The tangential acceleration is tangent to the path of the particle's motion. In circular motion turning effect would be greater if tangential acceleration(at=r𝝰)which is due to the change in speed is zero and centripetal acceleration which is due to a change in direction is equal to v2/r times.

Q194. Which one of the following is a greater work?

• A. +100 J
• B. -100 J
• C. -1000J✓
• D. +200J

Explanation: According to thermodynamics, a system performs work when it transfers energy to its surroundings by a mechanism that allows the system to voluntarily exert enormous forces on those surroundings. Work applied to the system denotes that something other than the heat effect known did something to improve the system's internal energy. The underlying system energy diminished as a result of its effort on anything external to the system. The system's work, or the work that the gas does, is positive. Consider the expansion of gas during heating. The system is being worked on negatively. An illustration would be a constant force acting on a cylinder's piston. If we talk in respect of work done: The maximum work done by a system = + 200 J If maximum work done on a system = – 1000J Since there is no condition given in the question, we will choose the maximum work done/greatest change in energy in general which is -1000 J.

Q195. At what angle will work be maximum?

• A. 0˚✓
• B. 90˚
• C. 45˚
• D. 30˚

Explanation: According to the equation: W=FScosθ If displacement is parallel to the direction of force(θ=00), Then the work done will be maximum. At θ=00 work will be positive and maximum and at θ=1800 work is negative as a force acts in the opposite direction of displacement.

Q196. An object of mass 2 kg is lifted vertically through a distance of 1.5 m. The work done in process is:

• A. 29.4 J✓
• B. 19.4 J
• C. 17.4 J
• D. 20.4 J

Explanation: As in this case the object is displaced against the force of gravity, so we need to find the work done against gravity. Work done against gravity=mgh m=2kg h=1.5m g=9.8N W=mgh = 2 x 1.5 x 9.8 = 29.4 J Note: As F=ma, in this case, acceleration=gravity so F=mg is the force that must be exerted on the object in the upward direction to lift it.

Q197. A particle executes S.H.M. with frequency f. The frequency of variation of its maximum or minimum kinetic energy is:

• A. f/2
• B. f
• C. 2f✓
• D. 4f

Explanation: K.E=½ mw2(x02-x2) = ½ mw2 (x02- x02sin2 wt) =½ mw2 x02(1-sin2 wt) =½ mw2 x02cos2 wt =½ mw2 x02(1+cos2 wt/2 ) =¼ mw2 x02 +¼ mw2 x02cos2wt =2f Hence the frequency of K.E. is 2ω or 2f In SHM, a particle has zero or minimum velocity at extreme points and maximum velocity at mean points. With the help of a diagram, we can see that in one time period of the pendulum (starting from the left extreme point) K.E. reaches zero to a maximum of two times. During one complete oscillation, the kinetic energy will become maximum twice. Therefore the frequency of kinetic energy will be 2f.

Q198. A source of sound moves towards a stationary observer with a speed one third of sound. If the frequency of the sound from the source is 100 Hz, the apparent frequency of the sound heard by the observer is:

• A. 60 Hz
• B. 100 Hz
• C. 200 Hz
• D. 150 Hz✓

Explanation: Doppler effect formula is=F0 = (v+v0/v +vs) fsf0= observed frequencyv=velocity of sound in air (330m/s)vs velocity of the sourcev0= velocity of the observerIf we rearrange the equation according to our case which is when a source is moving towards a stationary observer, the equation we get is:F0 = fs(v/v-vs)vs= one third of velocity of sound = 330/3 = 110v0= 0 because the observer is stationaryThe sign is negative since the source is moving toward the observer and the sign would be positive in case the source is moving away from the observer.Solution:F0 = 100(330/330-110)F0= 100(330/220) = 100x 1.5 =150HzHz

Q199. For a certain organ pipe, three successive resonance frequencies are observed at 425, 595, and 765 Hz. The speed of the sound in air is 340 m/s. The pipe is:

• A. Closed pipe of length 1 m✓
• B. Closed pipe of length 2 m
• C. Open pipe of length 1 m
• D. Open pipe of length 2 m

Explanation: To find out which organ pipe is used, first, we will take the ratio of 3 observed harmonics: 425:595:765 5x 85 : 7x 85 : 9x 85 Since each successive harmonic is an odd number; the organ pipe is most likely a closed one and 85Hz is common for all so it is the fundamental frequency or f=425/5 = 85Hz f=595/7 =85Hz f=765/9= 85Hz Now: For fundamental frequency: L =v/4f = 340/85x4 = 1m answer!

Q200. A metallic circular ring is suspended by a string and is kept in a vertical plane. When a magnet is approached towards the ring, then it will:

• A. Remain stationary
• B. Get displaced away from the magnet✓
• C. Get displaced towards the magnet
• D. Nothing can be said

Explanation: When the magnet is brought closer, the magnetic flux through the ring changes, and according to Lenz’s law current is induced in the ring that will produce its own magnetic field which opposes the change in flux through the ring. Therefore, the induced magnetic field of the ring will oppose the field of the magnet(as according to Lenz law it opposes the change that induced it in the first place). Due to the repulsion, the ring moves away from the approaching field as shown below.

Q201. The cause of induced emf is:

• A. Rate of change of magnetic flux✓
• B. Decrease in magnetic flux
• C. Increase in magnetic flux
• D. Change in magnetic flux

Explanation: The most basic cause of Induced EMF is a change in Magnetic flux with time in accordance with Faraday law: e=dθ/dt As flux(Փ)= B→.A → = So if our B or magnetic flux change with time then EMF will be induced Or if our A or area changes with time; it will also induce EMF. Or if orientation between B and A changes then Emf will be induced.

Q202. A negatively charged particle initially at rest is placed in an electric field that varies from point to point. There are no other fields. Then:

• A. The particle moves along the electric line of force passing through it.
• B. The particle moves opposite to the electric line of force passing through it.✓
• C. The direction of acceleration of the particle is tangential to the electric line of force at every instant.
• D. The direction of acceleration of the particle is normal to the electric line of force at every instant.

Explanation: A negatively charged particle experiences a force opposite to the direction of the electric field (or electric lines of force).Since it starts from rest, it accelerates opposite to the field direction, following the line of force but in the opposite sense.The acceleration is along the line of force, not tangential or normal

Q203. A coil is rotated in a uniform magnetic field about an axis perpendicular to the field. The emf induced in the coil would be maximum when the plane of the coil is:

• A. Parallel to the field✓
• B. Perpendicular to the field
• C. At 45˚ to the field
• D. None of the given options are correct

Explanation: According to Faraday’s law when magnetic flux linking a circuit changes, an electromotive force is induced in the circuit proportional to the rate of change of flux linkage. So, when a coil is rotated in the uniform magnetic field about an axis passing through the center and perpendicular to the direction of the field then emf: emf= -dՓ/dt ՓB =BAcos𝝷 =-d(BAcos𝝷)/dt =-BA d/dt cos𝝷 = -BA =sin d𝝷/dt = emf= BAsin d𝝷/dt Hence emf↑ when sin𝝷 ↑ Sin𝝷 = max when𝝷 =𝞹 /2 B⟂A when plane ∥ B i.e. angle between the area vector and the magnetic field is π/2 so the angle between the plane of the coil and magnetic field is zero or the induced emf in the coil is maximum when cosθ is maximum or θ is zero means when the plane of the coil is parallel to the field as shown below. Note; If it is perpendicular then no emf would be induced and at 450 it would not be maximum.

Q204. The force of repulsion between two charges is considered as:

• A. Negative
• B. Positive✓
• C. May be positive or negative
• D. Cannot be determined

Explanation: According to Coulomb's law When the charges have opposite signs, the force is attractive (negative F), while if both charges have the same sign, the force is repulsive (positive F).F=k q1q2/r2

Q205. How much power is used in moving a 0.03 C charge from point A at a potential of 40 V to point B at 60 V, if this takes 2 seconds?

• A. 0.30 W✓
• B. 0.15 W
• C. 0.60 W
• D. 0.012 W

Explanation: First, we have to find the work done in moving charge from A to B W=q(VB-VA) W= 0.03(60-40) = 0.6j Now power used can be calculated as follow: p=W/t p= 0.6/2 p=0.3W

Q206. When the current is neither drawn from a source nor given to it then:

• A. E=VT✓
• B. VT>E
• C. E>VT
• D. Both “VT>E” & “E>VT”

Explanation: The potential difference between the terminals of a battery will be equal to the emf of the battery when there is no current. At this time, the potential drop across the internal resistance is zero. This only happens when there is no load placed on the battery which includes measuring the potential difference with the voltmeter. The terminal voltage will exceed the emf of the battery when current is driven backward through the battery, in at the positive terminal and out at its negative terminal. VT> E = terminal voltage is greater than emf only when the cell is being charged. E>VT= The emf of a cell is greater than its terminal voltage When current is drawn because there is some potential drop across the cell due to its small internal resistance.

Q207. A current carrying solenoid is cut into a ratio 1:3 such that both are independently connected with the same source of current. Now if the magnetic field of the first part is “BA” while the second part respectively is “BB” then what is true?

• A. BA=3BB
• B. BA=(BB)/3
• C. BA=BB✓
• D. BA=4BB

Explanation: Magnetic field in solenoid is independent of length and cross section area;B= 𝛍 nIn=I/Ln= number of turnsI=currentL=lengthB magnetic flux density 𝛍= magnetic Constant Even if solenoid is cut in any ratio; n would still remain the same because magnetic field in solenoid is independent of length and cross section area .If n remains same so will be the magnetic field

Q208. A proton is projected with a uniform velocity ‘v’ along the axis of a current carrying solenoid.

• A. The proton will be accelerated along the axis.
• B. The proton path will be circular about the axis.
• C. The proton moves along a helical path.
• D. The proton will continue to move with velocity ‘v’ along the axis.✓

Explanation: The proton is traveling in the same direction as the solenoid’s axis. Because the magnetic field inside the solenoid is homogenous and parallel to the solenoid, it has no effect on the proton's velocity and it is parallel to the magnetic field( net force on proton is zero) The angle between B and V= 00 According to Lorentz's formula F=q(VxB) or F=qVBsinΘ Here sinΘ =0 this means there will be no force due to the magnetic field at all hence the proton will continue to move with the same velocity along the axis. Since there is no effect on the velocity of the proton so the proton cannot be accelerated along the axis. The proton cannot move in a helical path also.

Q209. The de Broglie wavelength of a particle of mass 1 gram and velocity 100 ms-1 is:

• A. 6.63 x 10-35
• B. 6.63 x 10-34
• C. 6.63 x 10-33✓
• D. 6.63 x 10-32

Explanation: .de Broglie reasoned that matter also can show Wave-particle duality just like light, since light can behave both as a wave (it can be diffracted and it has a wavelength) and as a particle (it contains packets of energy hν). And also reasoned that matter would follow the same equation for wavelength as light namely, λ = h / p Where p is the linear momentum, as shown by Einstein. P=mv The de Broglie wavelength formula: λ=h/mv h=Plank’s constant = 6.63x10-34 m=1g=10-3kg ( 1/1000) v=100m/s λ=h/mv λ=6.63x10-34/ 10-3x100 = 6.63x10-33m

Q210. When light has exactly the same energy as the work done function of a metal surface then:

• A. No photoelectrons are produced
• B. No photoelectric effect is observed
• C. No photo electric current is produced✓
• D. All of these options are correct

Explanation: no photoelectric current is produced although photoelectrons are emitted they do not move or do not have kinetic energy as, hv = W ( work function = hv0) +Ek where Ek =0 and v=v0 The work function of a metal is the energy corresponding to the threshold frequency of the metal. Albert Einstein used the work function of a metal to describe the photoelectric effect. The maximum kinetic energy of the ejected electrons depended on the frequency of the incident photon and the work function. K.E.max= hf – φ. The work function of metal can be interpreted as the minimum bond energy or the bond energy of the surface electrons. If the energy of the incident photons is equal to the work function, the kinetic energy of the released electrons will be zero and no photoelectric current will be observed. The electron is trapped inside a potential well which is created by the effect of the nucleus and other electrons. The work function is the energy required for the electron to reach to the top of the well. So, rationally thinking, a photon of energy equal to the work function will excite the electron to the top of the well and then the electron will get de-excited back to the bottom; thereby preventing the ejection and “f” energy of incident photon equals to work function then the ejected photon will have zero kinetic energy because the incident energy of electron will just act as ionizing energy. In this, we can also observe that photoelectrons are initially produced and a photoelectric effect is observed but t is compensated hence no current can be observed.

Q211. If we use a light of photons having energy 2.4 eV then the stopping potential required will be:

• A. 2.4 V✓
• B. 2.6 V
• C. 2.5 V
• D. 0 V

Explanation: The formula for stopping potential is: K.Emax=leV0l Rearranging: V0= K.Emax/e =V0= 2.4ev/e V0=2.4 V answer! Stopping potential is defined as the potential required to stop the ejection of electrons from a metal surface when an incident beam of energy greater than the work potential of metal is directed on it. Stopping potential can never be zero.

Q212. Which of the following has maximum ionizing power?

• A. α✓
• B. β
• C. γ
• D. Neutron

Explanation: Alpha particles have the highest ionization power than the other two types of radiation owing to the fact that an 𝝰-particle is a doubly ionized helium nucleus, i.e. He+2. 𝞫-particles are simply electrons (e-1), They have moderate ionizing power and 𝝲-rays are uncharged EM radiation and have the lowest ionizing power among all. Therefore, out of the three, 𝝰-rays have the most electric charge and are the most massive. Hence, when they are passed through a substance, they tend to ionize the substance (by attracting and stripping off the electrons from it) than 𝞫-and 𝝲-radiation. X-rays are also a part of EM radiation, but still cannot ionize as powerful as 𝝰-rays. Whereas neutrons have no charge and hence no ionization power.

Q213. When we apply input at the non-inverting input of an operational amplifier then the output appears after:

• A. Amplification, phase shift of 180˚
• B. Amplification, phase shift of 60˚
• C. Amplification, no phase shift✓
• D. None of the given options

Explanation: An amplifier’s non-inverting input refers to the pin configuration. The non-inverting input is the terminal marked with a plus (+) sign, and the inverting input is marked with a minus (-) sign. These can also be referred to as positive and negative terminals. Non-inverting amplifier work on these rules: The Current Rule: No current flows into the inputs of the op-amp (I+=I-=0). The Voltage Rule: The output of the op-amp attempts to ensure that the voltage difference between the two inputs is zero (V+=V-). Non-inverting op-amp circuit. Consider the non-inverting op amp circuit shown above. According to the Voltage Rule, the voltage at the inverting (-) input will be the same as at the non-inverting (+) input, which is the applied voltage, Vin. The current going through R1 can then be given as Vin/R1. According to the Current Rule, the inputs draw no current, so all that current must then flow through R2. The output voltage can then be given as Vout=Vin+(Vin/R1)R2. The gain is then Vout/Vin=1+(R2/R1). The gain will never be less than 1, so the non-inverting op-amp will produce an amplified signal that is in phase with the input. A non-inverting op amp is an operational amplifier circuit with an output voltage that is in phase with the input voltage. Its complement is the inverting op amp, Hence Output is in phase with input and is amplified.

Q214. Which of the following is false?

• A. In P-type substance majority charge carriers are holes
• B. During forward biasing of a divide width of depletion region decreases
• C. Leakage current flows to minority charge carriers
• D. None of the given options✓

Explanation: All the options are true

Q215. Which of the following is not true about LEDs?

• A. There are two wires (called leads) attached to an LED
• B. While connecting to a circuit, the longer lead of LED is always connected to the positive terminal of the battery
• C. While connecting to a circuit, the shorter lead of LED is always connected to the positive terminal of the battery✓
• D. LED can be used to detect weak current

Explanation: While connecting to a circuit, the shorter lead of the LED is always connected to the positive terminal of the battery. Explanation: A Light Emitting Diode (LED) is a semiconductor device, which can emit light when an electric current passes through it. To do this, holes from p-type semiconductors recombine with electrons from n-type semiconductors to produce light. The wavelength of the light emitted depends on the bandgap of the semiconductor material. Harder materials with stronger molecular bonds generally have wider band gaps. The LEDs have 2 leads. The lead connected to the positive terminal of the battery is called anode and the lead connected to the negative terminal is called cathode. The longer lead is always connected to the positive terminal because a Thick plate of impure copper is made the positive electrode (anode) and shorter t the negative terminal. LED is also used to detect weak electric currents But the major use of LED (Light Emitting Diodes) is to illuminate objects and even places.

Q216. Change the indirect narration into direct narration He said that he could swim under water for two hours.

• A. He said, “I can swim under water for two hours.”✓
• B. He said. “I can swim under water for two hours.”
• C. He said, “I can swim under water for two hours”.
• D. He said“, I can swim under water for two hours.”

Explanation: He said that he could swim under water for two hours.The original sentence is a statement about someone's ability, and the correct reported speech uses the verb "could" (not "can") to indicate a past ability.

Q217. Change into direct narration Harry asks if he might smoke.

• A. Harry told, “May I smoke”?
• B. Harry said, “may I smoke?”
• C. Harry said, “May I smoke.”
• D. Harry asked, “May I smoke?”✓

Explanation: The original sentence is a request for permission, and the correct reported speech uses the verb "asked" followed by the exact question, using the correct word order and punctuation.

Q218. Change into indirect narration They said, “How beautiful she looks!”

• A. They exclaimed with wonder that she look very beautiful.
• B. They exclaimed with sorrow that she looks very beautiful.
• C. They exclaimed with wonder, that she looked very beautiful.
• D. They exclaimed with wonder that she looked very beautiful.✓

Explanation: The original sentence is an exclamation of admiration, and the correct reported speech uses the verb "exclaimed" to convey the strong feeling, along with the phrase "with wonder" to indicate the tone.

Q219. Change the Narrations of following sentenceShe said, “When I was enjoying youth, I watched movies”.

• A. She said that when she enjoyed youth she watched movies.
• B. She said when she was enjoying youth, she watched movies.✓
• C. She said that when I had enjoyed I had watched movies.
• D. She inquired that when they were enjoying and watching movies.

Explanation: The original sentence is a statement about the past, and the correct reported speech maintains the same tense and pronouns.

Q220. Change into indirect narration It's time we began planning our holidays,' he said.

• A. He said that it is time they began planning their holidays.
• B. He said that it was time they had begun planning their holidays.
• C. He said it is time they begin planning their holidays.
• D. He said that it was time they began planning their holidays.✓

Explanation: He said that it was time they began planning their holidays.The original sentence is a statement about the timing of planning holidays, and the correct reported speech uses the past tense "was" to match the original sentence's tense.