Etea Mdcat 2011 — Solved Past Paper with Answers

Q1. We need _ guidelines to start with.

• A. a few✓
• B. any
• C. little
• D. some

Explanation: ‘A few’ refers to a certain known number of things, while some is used when the number is indefinite. ‘Any’ and ‘little’ do not grammatically make sense in this context. Hence ‘a few’ is correct.

Q2. The authorities have _ that the plane to Beirut was hijacked over the Indian Ocean.

• A. Assured
• B. Confirmed✓
• C. Committed
• D. Ensured

Explanation: Confirmed means when the truth or validity of something is attested to. In the context of this sentence, 'confirmed' makes the most sense. Assured means characterized by certainty or security; to be guaranteed Committed means dedicated to something. Ensured means to make sure of something.

Q3. She has let _ her house fully furnished to a Korean couple.

• A. out✓
• B. at
• C. up
• D. in

Explanation: The phrasal verb 'let out' means to allow someone to use a room, building, etc. in exchange for money. It is the most suitable option for this sentence. Let at is not a phrasal verb. Let up means to relax one's efforts. Let in means to allow something to enter.

Q4. Your _ too long; you had better go to the hairdresser today.

• A. hair is✓
• B. hair are
• C. hairs are
• D. hairs is

Explanation: Hair is an uncountable noun, so it will be used in the singular form. The verb used with hair will also be singular, so the correct option is 'hair is'.

Q5. I have no _ to listen to the budget speech.

• A. Trouble
• B. Convenience
• C. Patience✓
• D. Perseverance

Explanation: Patience is the ability to wait, to continue doing something despite difficulties, or to suffer without complaining or becoming annoyed. Trouble means difficulty or problems. Convenience is the state of being able to proceed with something without difficulty. Perseverance is persistence in doing something despite difficulty. Out of the given options, patience is the most suitable word here.

Q6. You can always count on me. I will not let you _.

• A. alone
• B. down✓
• C. off
• D. through

Explanation: Letting you down means failing to support you. Option B is correct.

Q7. Styles _ popular in the 1950s are reappearing in high fashion boutiques.

• A. what have been
• B. which have been
• C. that have been
• D. that were✓

Explanation: "That were" is the correct option.

Q8. Waeem _ him MD for many years, but he is rather unhappy with his salary.

• A. is working in
• B. is serving
• C. is working for
• D. has been working✓

Explanation: Mistake

Q9. Tahira as well as her brother _ responsible for the loss and they must be made to make up for it:

• A. is✓
• B. are
• C. were
• D. have been

Explanation: Option A is correct.

Q10. She _ her parents. They must be worried about her health.

• A. had better call
• B. had better called
• C. had better to call
• D. better call✓

Explanation: Option D is correct.

Q11. He _ before the interview board.

• A. was afraid to appear
• B. was afraid of appearing✓
• C. was afraid of appearing
• D. feared appearance

Explanation: The sentence is in past continuous tense. So option B is correct.

Q12. He said, "If I were you, I would protest." This can be indirectly reported as:

• A. if he had been me, he would have protested✓
• B. he advised us to protest
• C. if he were me, he would protest
• D. if he had been I, he would have protested

Explanation: He said that/ told that if he had been me, he would have protested. Option A is correct.

Q13. _ in the world.

• A. our's is not one of the quickest response system
• B. our is not one of the quickest response system
• C. ours is not one of the quickest response system✓
• D. our is not one of the quickest response system

Explanation: Ours is correct, while our or our’s is incorrect according to the use of it in this sentence. It shows possession, and our’s (our is) isn’t correct, and ours fits the best here.

Q14. A good businessman should not be unscrupulous while making profits The underlined word means:

• A. unprincipled✓
• B. careless
• C. illegal
• D. miserly

Explanation: Unscrupulous means unprincipled or unethical

Q15. "Cynic' and _ are synonyms:

• A. skeptic✓
• B. secret
• C. solitary
• D. truthful

Explanation: Cynic means someone who questions popularly accepted opinions. OR a curious critic, OR someone who believes human conduct wholly depends on self-interest.

Q16. 'Professional' and '_' are antonyms.

• A. unemployed
• B. entrepreneur
• C. amateur✓
• D. capitalist

Explanation: The opposite of a professional person is someone who is incompetent and engages in an activity on an unpaid basis. This fits the definition of 'amateur', therefore option 'C' is the right answer.

Q17. Secrets leak when the _ are many.

• A. Enemies
• B. Ill-wishers
• C. Confidants✓
• D. Detractor

Explanation: A confidant is a person whom one can entrust his/her secrets to. Having many confidants means that the secrets are beheld by many people and consequently, there is a greater chance of betrayal and disclosure of secrets. Thus, this is the correct answer.

Q18. The guard looked at me _ and then asked me to identify myself.

• A. dangerously
• B. hurriedly
• C. suspiciously✓
• D. nervously

Explanation: The duty of a security guard is to patrol and monitor activity at a location or property. If he is asking someone to identify himself, then it is obvious that the guard finds him suspicious. Thus, option ‘C’ should be the right answer.

Q19. She tried to _ my question, but i persisted in having an answer.

• A. Refrain
• B. Evade✓
• C. refuse
• D. deny

Explanation: Evade means to escape or avoid something. So option B is correct.

Q20. Her _ lasted for one month. They were the longest wedding celebrations in that area.

• A. rituals
• B. matrimonial
• C. nuptials✓
• D. rites

Explanation: Here, ‘nuptials’ fits the best. Option ‘B’ could also be considered, but only if it was a matrimonial marriage instead of only matrimonial, because it makes no sense.

Q21. Which of the following diseases is NOT caused by bacteria?

• A. tetanus
• B. small pox✓
• C. tuberculosis
• D. diptheria

Explanation: Smallpox is caused by a virus, the variola virus, not a bacterium. Tetanus is caused by a bacterium called Clostridium tetani. Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis. Diphtheria is caused by strains of bacteria called Corynebacterium diphtheriae.

Q22. Round worms, which have body cavities that are partially lined with mesoderm, are classified as:

• A. Acaelomate
• B. ceolomates
• C. Pseudocoelomates✓
• D. Deuterostomes

Explanation: A pseudocoelomate is an organism with a body cavity called a pseudocoelem that is not derived from the mesoderm, as in a true coelom, or body cavity. In invertebrates, the pseudocoelom is filled with fluid that lies between the mesoderm layer of the external body wall and the endoderm layer of the gut. But this is not a true coelem as it originates from the blastocoel, not the archenteron of Gastrula, which is the true site of origin of coelem. Roundworms in the phylum Aschelminthes are pseudocoelemates.

Q23. The hypothesis of Ronald Ross relating to malaria was:

• A. plasmodia are the cause of malaria
• B. bad air is involved in the spread of malaria
• C. Mosquitoes are possible carriers of Plasmodium.✓
• D. Malaria is caused by bad air coming from marshy places.

Explanation: Plasmodia are the parasites that cause malaria. Ronald Ross conducted an experiment on Anopheles mosquitoes in 1897, which had previously fed on a malarious patient. He found the plasmodium in the stomachs of these mosquitoes and concluded that they are carriers of the parasite and cause the spread of malaria.

Q24. Crustaceans are the only arthropods that have:

• A. chitin in their exoskeleton
• B. chlicitae
• C. three pairs of legs
• D. two pairs of antennae✓

Explanation: Crustaceans are the only arthropods with two pairs of antennae, so option D is correct. All arthropods have chitin in their exoskeleton. Chelicerae are mouth parts present in some arthropods like arachnids, horseshoe crabs, and sea spiders, but they are absent in crustaceans. Crustaceans have five pairs of legs, not three.

Q25. A cloned baby sheep "Dolly" was attributed to

• A. Four Parents
• B. Three Parents
• C. Two parents
• D. One Parent only✓

Explanation: Cloning is a mode of asexual reproduction through which genetically identical copies of an organism are produced. 'Dolly' the sheep was cloned from one adult somatic cell and is therefore attributed to one parent only.

Q26. In spiders, the organs that contain the silk glands are called

• A. spinneret✓
• B. Carapace
• C. Medriporite
• D. Tube feet

Explanation: Spiders, which belong to the phylum Arthropoda, are predators who trap their prey by producing silk threads. The spinneret is the silk-producing organ in spiders.

Q27. Which of the following bird structures are especially adapted to support flight?

• A. Cloacas
• B. Bills
• C. Gizzard
• D. chest muscles✓

Explanation: The shape of the sternum and chest muscles aid birds in flight.

Q28. Which of the following is composed of lipids?

• A. Some hormones✓
• B. Enzymes
• C. Skin terdons
• D. insulin

Explanation: Steroid hormones are derived from lipids. They include testosterone, estrogen, and cortisol, among others.

Q29. The rate of breathing of a child of 5 years is about:

• A. 44 times/minute
• B. 40 times/minute
• C. 25 times/minute✓
• D. 20 times/minute

Explanation: The breathing rate decreases with age. Some average breathing rates are given below: 2-5 years= 25–30 breaths/min 5-12 years= 20 to 25 breaths /min >12 years= 15 to 20 breaths/min Option C is most suitable here, as 25 breaths/min falls between the first two age groups given.

Q30. The middle lamella of the cell wall is composed of:

• A. Cellulose
• B. pectin✓
• C. Lignin
• D. Murein

Explanation: The middle lamella is made up of pectin in the form of calcium and magnesium pectates. It is present between the primary cell walls of two cells and cements them together.

Q31. Nicotine in tobacco

• A. decreases the heart rate
• B. decreases blood pressure
• C. block the transport of oxygen✓
• D. paralyzes cilia

Explanation: Nicotine in tobacco increases the heart rate and blood pressure. It causes narrowing of the arteries, which blocks oxygen transport in the blood. Tar in tobacco paralyzes cilia.

Q32. Stream of chloroplasts carries the fixation of:

• A. Nitrogen
• B. Oxygen
• C. Carbon monoxide
• D. carbon dioxide✓

Explanation: The equation for photosynthesis is 6CO2+6H2O→C6H12O6+6O2. Light dependent and light independent reactions take place in the chloroplast. The light dependent reactions use light energy and take place in the thylakoid membrane. The light independent reaction takes place in the stroma of chloroplast. The enzyme rubisco helps the fixation of carbon dioxide present in the air which combines with RUBP during the Calvin Cycle, the ultimate product of which is glucose. The process which converts inorganic carbon in the form of CO2 to organic carbon in the form of carbohydrates is known as carbon dioxide fixation.

Q33. The valves between the right atrium and right ventricle is called:

• A. bicuspid valve
• B. tricuspid valve✓
• C. pulmonary valve
• D. semi lunar valve-

Explanation: The valve between the right atrium and the right ventricle is the tricuspid valve.

Q34. Anthocyanins are various types of colorful pigments present in the

• A. chloroplasts
• B. chromoplasts
• C. leucoplasts
• D. vacuoles✓

Explanation: Vacuoles are specialized cell organelles that perform storage and digestive functions. Water-soluble substances like anthocyanin pigments are found in the vacuolar sap.

Q35. Antibodies are produced by

• A. red blood cells
• B. platelets
• C. B-lymphocytes✓
• D. Hormones

Explanation: B cells exclusively synthesize antibodies.

Q36. Phage virus secretes an enzyme called "lysozyme" form its

• A. Head region
• B. Tail region✓
• C. neck region
• D. capsule region

Explanation: Lysozyme is an enzyme secreted by the tail region during the penetration phase.

Q37. Much of mechanical digestion takes place in the

• A. oesophagus
• B. mouth
• C. stomach✓
• D. duodenum

Explanation: Stomach as it churns and mixes solid bolus into small pieces converting it into acidic chyme.

Q38. H.I.V contains

• A. two RNAs✓
• B. a single R.N.A
• C. D.N.A and R.N.A
• D. D.N.A

Explanation: HIV contains two identical RNAs enclosed within capsid

Q39. The amount of energy in food is measured as:

• A. ATP
• B. Calories✓
• C. ADP
• D. Carbohydrates

Explanation: Amount of energy in food is measured in calories.

Q40. The inheritable form of immunity through mother's milk is:

• A. active immunity
• B. innate immunity
• C. passive immunity✓
• D. Acquired immunity

Explanation: The immunity acquired through mother’s milk is passive immunity.

Q41. Which of the following is NOT an innate behavior?

• A. a body mammal sucking milk
• B. a dog looking for its food dish✓
• C. a worm moving away from bright light
• D. a spider spinning a web

Explanation: Dogs learned to look at food in a dish since they associated food with the dish.

Q42. Entamoeba belongs to the phylum:

• A. sporozoa
• B. sarcodina✓
• C. mastigophora
• D. microspora

Explanation: Entamoeba are pseudopod-forming protozoan parasites in the subphylum Sarcodina.

Q43. A non-specific defense reaction to tissue damage caused by injury or infection is known as:

• A. active immunity
• B. inflammatory response✓
• C. c
• D. d

Explanation: Inflammation is a response triggered by damage to living tissues. The inflammatory response is a defence mechanism that evolved in higher organisms to protect them from infection and injury.defense

Q44. Nuclear mitosis occurs in the kingdom of

• A. Monera
• B. Protista
• C. Plantae
• D. Fungi✓

Explanation: Fungal mitotic divisions are intranuclear. In this mitosis, the spindle fibers are formed inside the nucleus.

Q45. The protein that helps other cells resist viral infection is

• A. Pencillin
• B. Histamine
• C. Interferon✓
• D. Antigens

Explanation: Interferons (IFNs) are cytokines that help other cells resist viral infection.

Q46. Rust and smut belong to the phylum

• A. zygomycota
• B. ascomycota
• C. basidiomycota✓
• D. deytromycota

Explanation: Rust and Smut, both diseases of plants, are caused by pathogenic fungi belonging to the class Basidiomycetes.

Q47. A network of tubules that runs through compact bone is called the

• A. Haversian canal✓
• B. Periosteum
• C. marrow
• D. Joint

Explanation: Haversian canals are a series of tubes around narrow channels formed by lamellae that run through compact bone. The Haversian canals surround blood vessels and nerve fibers throughout the bone and communicate with osteocytes.

Q48. Club-mosses are also called

• A. psilopsida
• B. sphenopsida
• C. lycopsida✓
• D. pleropsida

Explanation: The scientific name for Club Mosses is Lycopsida.

Q49. Hormones produced from cholestrol are called

• A. protein hormoes
• B. Non-steroid hormones
• C. steroid hormones✓
• D. poptide hormones

Explanation: Hormones produced from cholesterol are called steroid hormones. Examples include the sex hormones testosterone and estrogen.

Q50. Lycopersicum esculenium is commonly known as

• A. Gram
• B. Tomato✓
• C. Potato
• D. Red pepper

Explanation: The tomato is the edible, often red fruit/berry of the nightshade family Solanaceae, Lycopersicum esculentum, commonly known as a tomato plant.

Q51. The rate of metabolism is regulated by:

• A. PTH
• B. Thyroxine✓
• C. Aldosterone
• D. Calcitonin

Explanation: Thyroxine is secreted by the thyroid gland and is a vital hormone that controls functions like digestion, heartbeat, and muscular contraction, hence controlling body metabolism.

Q52. Plant cells synthesize sugar in the;

• A. Thylakoid
• B. Grana
• C. Stroma✓
• D. Christa

Explanation: Plant cells synthesise sugar in stroma of chloroplast because the enzymes essential for carbohydrate synthesis are present in the stroma.

Q53. The process of cell division result in:

• A. two daughter cells✓
• B. sister chromatids
• C. mitosis
• D. unregulated growth

Explanation: Cell division Mitosis or meiosis results in the formation of daughter cells from the division of the parent cell.

Q54. Chlorophyll II is protected from intense light by

• A. plant hormones
• B. carotenoids✓
• C. plant enzymes
• D. water present in mysophyll tissue

Explanation: Carotenoids are the photoprotective pigments that absorb light of high intensity and transfer the energy to chlorophyll for photosynthesis, thereby playing an important role in photosynthesis.

Q55. Malphigian tubules convert nitrogenous waste into:

• A. urine
• B. ammonia
• C. uric acid✓
• D. urea

Explanation: Malphigian tubules are excretory organs of cockroaches that are a tubular network that converts nitogenous waste into uric acid. It absorbs nitrogenous waste from the hemocoel, which is then converted to uric acid, which is then excreted out through the hind gut. Uric acid is insoluble in water and is excreted as pellets or paste by insects and birds as a water-saving measure.

Q56. Chlorosis in plants is caused by the deficiency of:

• A. nitrogen
• B. magnesium
• C. potassium
• D. both a and b✓

Explanation: Chlorosis is the loss of the normal green color of leaves due to insufficient chlorophyll for photosynthesis. Its possible causes include nutritional deficiencies, for example, deficiency of minerals like iron, nitrogen, and magnesium.

Q57. The changes in the biochemical composition and physiology occurring at regular intervals in 24 hours is termed as:

• A. gioannual rhythm
• B. lunar rhythm
• C. circadian rhythm✓
• D. tidal rhythm

Explanation: Circadian rhythms are physiological, mental, behavioural changes in animals that follow a 24 hour cycle while lunar and tidal rhythms represents these changes but they are influenced by position of moon around the earth and tidal activity respectively, usually time period of lunar rhythms is somewhere near 29 days while that od tidal rhythms is near 12 hrs.

Q58. The earlyis fall of leaves and fruits in plants in caused by the deficiency of:

• A. phosphorus✓
• B. potassium
• C. magnesium
• D. nitrogen

Explanation: Phosphorus is the nutrient essential for prevention of early fall of leaves and fruits in plants also called abscission while magnesium, nitrogen and potassium are necessary to prevent colorosis

Q59. The organisms that developed with two heads and one trunk are called

• A. identical twins
• B. Siamese twins✓
• C. dizygotic twins
• D. fraternal twins

Explanation: Siamese twins are born with two heads and one trunk; identical twins have the same genome and sex; fraternal twins are the result of the fertilization of two eggs by two sperm and may or may not have the same gender; fraternal twins are also called dizygotic twins.

Q60. Hydathodes are

• A. hormones secreting glands
• B. water secreting glands✓
• C. nectar secreting glands
• D. enzymes secreting glands

Explanation: Hydathodes are holes in leaf magrin through which water is secreted out during guttation.

Q61. A Punnet square is used to determine the

• A. result of mitosis
• B. result of meiosis
• C. actual outcome of a cross
• D. probable outcome of cross✓

Explanation: A punnett square is always used to determine the POSSIBLE OUTCOME of a cross and never an actual one because an actual one can never be determined priorly.

Q62. The number of chromosomes of tobacco plant are

• A. 43
• B. 1.29
• C. 0.43
• D. 24✓

Explanation: The total number of chromosomes present in a tobacco plant is 24, therefore option 'D' is correct.

Q63. During replication, which sequence of nucleotides would bond with the DNA sequence TATGA

• A. AUAGA
• B. ATACA
• C. UAUGU
• D. ATACT✓

Explanation: Nucleotides are the building blocks of nucleic acids, i.e., DNA and RNA. A nucleotide consists of a sugar molecule attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). While in RNA, thymine (T) is replaced by uracil (U). The bases present on the two strands of DNA pair through hydrogen bonds in a specific manner. Following the above rules, T is complementary to A A is complementary to T T is complementary to A G is complementary to C A is complementary to T Thus the strand complementary to the strand containing TATGA bases should contain ATACT bases.

Q64. All the following are growth hormones, except

• A. phytohormones✓
• B. Gibberllin
• C. auxins
• D. cytokinesis

Explanation: All plant hormones are collectively known as growth hormones. They include growth promoters, e.g., auxins, cytokinins, gibberellins, etc. as well as growth inhibitors such as abscisic acid, etc. All of the options except option ‘A’ are growth hormones; thus, option ‘A’ is the correct answer. This division is further explained by the following diagram:

Q65. In grapes and mangoes, the INFLORESCENCE is

• A. panicle✓
• B. multiparous cyme
• C. capitulum
• D. umbel

Explanation: A panicle is a branched inflorescence in which each branch has more than one flower. Major examples of plants having such inflorescences are grapes and mangoes. They are shown below, respectively.

Q66. A cross between dissimilar individuals to bring together their best characteristics is called

• A. Genetic Engineering
• B. Hybridization✓
• C. Inbreeding
• D. Sequencing

Explanation: Hybridization involves the crossing of dissimilar individuals to bring together the best of both parents in the offspring. It leads to variation among species. From the above statements, the definition of hybridization corresponds to the statement of the question. Thus, option ‘B’ is correct.

Q67. Organisms that contain genes from other organism are called

• A. mutagenic
• B. transgenic✓
• C. glones
• D. sequencing

Explanation: An organism whose genome has been altered by the introduction of one or more foreign DNA molecules from another species by artificial means. This explanation corresponds to the statement of the question. Thus, option ‘B’ is the correct answer.

Q68. The ozone layer present in the

• A. troposphere
• B. stratosphere✓
• C. mesosphere
• D. atmosphere

Explanation: Ozone Layer: It is a thin part of Earth's atmosphere that absorbs almost all of the sun's harmful ultraviolet light. EARTH’S ATMOSPHERIC LAYERS: Earth's atmosphere has a series of layers, each with its own specific traits. Moving upward from ground level, these layers are called the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The Ozone layer is around 15–30 km above the earth's surface. From the above diagram, we know that this region lies in the stratosphere. Thus, option ‘B’ is correct.

Q69. An inherited characteristic that increases an organism's ability to survive and produce in its specific environment is called

• A. Radiation
• B. Adaptation✓
• C. Vestigial organ
• D. Speciapion

Explanation: Inheritance characteristics refer to traits that are passed from parent to offspring during reproduction. Adaptation is any heritable trait that helps an organism, such as a plant or animal, survive and reproduce in its environment.

Q70. C.F.C gases are produced from

• A. burning of coal✓
• B. burning of charcoal
• C. automobile engines
• D. refrigeration and air conditioning

Explanation: Chloroflorocarbons are nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine. They react with the ozone and destroy it, making the layer thinner and allowing ultraviolet (UV) radiation to pass through it and fall on the earth's surface. This UV radiation can cause skin cancer and other ailments in humans and also affect plants and animals. The main source of CFC production is Coal combustion i.e. burning of coal. Among the given options, option A is correct because, unlike the rest, CFCs are released into the atmosphere, not produced.

Q71. The area where ultra voilet radiations are intense is the

• A. Alphine forests
• B. Boreal forests
• C. Arctic tundra
• D. Alpine tundra✓

Explanation: Among all the options, alpine tundra is at the highest elevation (about 12000 ft and above), and it has the most sunlight hours. Thus, the UV level in the alpine tundra is the highest.

Q72. A woman is homozygous for A negative blood type. A man has an AB-negative blood type. What is the probability that tha couples child will be type B negative?

• A. 0%✓
• B. 25%
• C. 50%
• D. 75%

Explanation: There is zero possibility that their offspring will have a B-negative blood type

Q73. A bird's wings are homologous to

• A. fishes tail fin
• B. dog's front legs✓
• C. mosquitoes wings
• D. alligator's claws

Explanation: Homologous Organs: These organs have similar anatomical structures but perform different functions. They are the result of divergent evolution. A human's arm, a dog's leg, a bird's wing, and a whale's flipper are all homologous. The same bones are found in each structure; they only differ in their size and shape.

Q74. All of the following are derived from mesoderm except:

• A. Muscles
• B. Liver✓
• C. Gonads
• D. Blood vessels

Explanation: GERM LAYERS: A germ layer is a group of cells in an embryo. There are 3 germ layers: the endoderm (inner layer), the ectoderm (outer layer), and the mesoderm (middle layer). All the parts mentioned are formed by mesoderm except for the liver, which is a product of endoderm.

Q75. The diameter of Histone is

• A. 1 nm
• B. 2 nm✓
• C. 3 nm
• D. 4 nm

Explanation: A histone is a protein that provides structural support to a chromosome. It is composed of mostly positively charged amino acid residues such as lysine and arginine. Histone is approximately 2 nm wide.

Q76. What is the most important source of water pollution in Pakistan?

• A. Industries
• B. Transportation
• C. Mining Industry
• D. Agricultural and municipal wastage✓

Explanation: Contamination of water bodies is called water pollution. Pakistan is an agricultural country. The root cause of water pollution in Pakistan arises here. The farmers use tons of water for their fields and crops and then dump all the contaminated water into lakes and rivers. In addition to that, the municipal committees are least bothered about the pollution caused by the garbage they throw in the water bodies. The industries also play a role in this, but the formerly mentioned points are the main causes of destruction. Thus, we will go for option D.

Q77. The number of nitrogenous bases common in both DNA and RNA are

• A. 2
• B. 3✓
• C. 5
• D. 4

Explanation: Building blocks of nucleic acids, i.e., DNA and RNA. A nucleotide consists of a sugar molecule attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). In RNA, thymine (T) is replaced by uracil (U). Thus, adenine, cytosine, and guanine are common in DNA and RNA.

Q78. The genetic potential for one type of cell from a multicellular organism to generate a whole new organism is called

• A. unipotent
• B. multipotent
• C. totipotent✓
• D. pluripotent

Explanation: Totipotent is an immature cell that is capable of giving rise to any cell type or even a complete embryo.

Q79. Which sequence correctly describes the route sperm take through the human male reproductive system?

• A. vas deference, urethra, epididymis
• B. Epididymis, vas deference, urethra✓
• C. Epididymis, urethra, vas deference
• D. Urethra, epididymis, vas deference

Explanation: The correct sequence of transport of sperms is: Seminiferous tubules → Rete testis → Vasa efferentia → Epididymis → Vas deferens → Ejaculatory duct → Urethra → Urethral meatus.

Q80. In chlorophyll 'a', the group attached to prophyrine ring is

• A. hydroxyl group
• B. methyl group✓
• C. carboxyl group
• D. aldehyde group

Explanation: Diagram given below:

Q81. The anion size are larger than its atomic size because:

• A. the addition of electron occupies more space
• B. it increases the effective nuclear charge
• C. the repulsion between electrons increases with the addition of electrons✓
• D. the attraction between electrons and the nucleus increase

Explanation: An anion is formed when an electron is added to an atom and it is negatively charged. The size of the anion is greater than that of its parent atom because the total number of electrons is greater than the total number of protons, so the attraction between the positively charged protons in the nucleus and the valence electrons decreases. The repulsion between similarly charged electrons increases, so the anion size is greater. Option A is incorrect as electrons are added to an already-present shell and no extra space is required to make room for them. Option B is incorrect as the nuclear charge does not change since the proton number remains constant. Option D is incorrect as the attraction between the nucleus and electrons does not increase but decreases since the nucleus hold on the valence electrons decreases.

Q82. Which one would you class it as more metallic in character?

• A. As
• B. Bi✓
• C. C
• D. Sb

Explanation: Metallic character increases from top to bottom in a group as the shielding effect increases, so the tendency to lose valence electrons increases. Whereas metallic character decreases across the period from left to right as effective nuclear charge increases, the tendency to lose electrons decreases. Out of all 4 options, Bi has the greatest shielding of valence electrons and the least ionization energy, so it has the greatest tendency to lose electrons and therefore the greatest metallic character.

Q83. Hydration energy is the heat evolved or absorbed when:

• A. one mole of gaseous ions is dissolved in one mole of water
• B. one mole of ions in solid state is dissolved in one mole of water.
• C. one mole of gaseous ions is dissolved in water to give infinitely dilute solution✓
• D. one mole of ions in solid state is dissolved to form concentrated solution

Explanation: Hydration energy is defined as ‘the energy released when one mole of gaseous ions dissolves in water to give an infinitely dilute solution’. Infinitely dilute solution can be defined as the term in which a solution contains so much solvent that if one adds more solvent to it, there will be no change in the concentration of the solution. Attraction occurs between the water molecules and the ions of the solute, and the solute particles interact only with the solvent, not each other. Hydration energy is always negative, meaning it is exothermic and energy is always released. Option A is incorrect as an excess amount of water is required.

Q84. The behavior of PbCl and PbCl2 respectively are:

• A. ionic and covalent✓
• B. covalent and ionic
• C. covalent and coordinate covalent
• D. ionic and coordinate covalent

Explanation: In PbCl₂, the charge on Pb is +2, and in PbCl4, the charge on Pb is +4. The greater the charge on a cation, the greater the tendency to form a covalent bond as it's polarizing power increases due to higher charge/size ratio, so PbCl4 is covalent. 4 electron pairs are shared between lead and chlorine, so options C and D are eliminated as a lone pair is not donated. Option B is incorrect, as in PbCl₂, lead loses two electrons and one electron is gained by each chlorine atom, forming an ionic bond, not a covalent bond.

Q85. Select the correct order in ionic behavior:

• A. AIF3 > AlBr3 > AICI3 >>AF3
• B. AICI3 > AIF3 >AIBr3 >All3
• C. AICI3>AIBrs5>AB2 >AIF3
• D. AIF3 > AICI3 > AIBr5 >All3✓

Explanation: The atomic size of the group 7 atoms increases moving down the group, while the charge is the same, -1 for all of them. Iodine has the largest atomic size, and fluorine has the smallest. According to Fajan’s rule, the greater the size of an anion, the greater the covalent character and the lesser the ionic character. So aluminum iodide is the least ionic and aluminum fluoride is the most ionic, so the order will be: AlF3> AlCl3>AlBr3>AlI3

Q86. Select the most stable covalent hycride:

• A. BiH3
• B. NH3
• C. HF✓
• D. SbH3

Explanation: The most stable hydride will have the greatest electronegativity difference since the bond energy will then also be the greatest. Fluorine is the most electronegative element so it's electronegativity difference with hydrogen will be the greatest and it will be most stable as there will be greatest electrostatic attraction between hydrogen and fluorine

Q87. Potassium is found in nature as carnallite, its composition is:

• A. KAISI3O4
• B. KClMgCl2 6H2O✓
• C. KCL
• D. KCL.Al2O3. 2H2O

Explanation: The formula of carnallite is Cl3H12KMgO6, which can also be written as KClMgCl2.6H2O. None of the other options have these atoms in the correct ratios, so option B is correct.

Q88. Fajan's rule states that small, highly charged ions tend to form more:

• A. ionic compounds
• B. polymeric compounds
• C. covalent compounds✓
• D. coordination compound

Explanation: According to Fajan's rule, the smaller the size of the cation and the greater the charge on it, the greater the covalent character of an ionic bond as the polarizing power of the cation increases due to greater charge density. So in this case, the small, highly charged ion forms a covalent compound.

Q89. Beryllium, a member of alkaline earth metal, is almost as hard as:

• A. calcium
• B. Potassium
• C. iron✓
• D. magnesium

Explanation: The hardness of a substance can be quantified using the Mohs scale of mineral hardness, which is a qualitative ordinal scale from 1 to 10, describing the scratch resistance of various minerals through the ability of harder material to scratch softer material. The Mohs hardness of some elements are given below From these values, we see that beryllium has a hardness of 5.5, calcium has 1.75, potassium has 0.4, iron has 4, and magnesium has 2.5. Iron has the closest hardness to beryllium and is the correct option here.

Q90. Select the correct statement:

• A. Cholera, typhoid, and tetanus are well-known diseases caused by viruses.
• B. Dinoflagellates, euglenoids and slime moulds are placed under kingdom Monera
• C. Members of kingdom Protista are primarily aquatic✓
• D. Dinoflagellates are the chief 'producers' in the oceans

Explanation: This statement is correct. The kingdom Protista consists of a diverse group of eukaryotic microorganisms, many of which are found in aquatic environments. Protists can be found in freshwater, marine habitats, and even moist terrestrial environments. They include various organisms such as algae, protozoa, and slime moulds.

Q91. Refratory bricks used for furnace lining are formed by mixing and drying:

• A. MgO and clay✓
• B. MgCO3 and clay
• C. MgSO4 and clay
• D. MgCO3 and CaCO3

Explanation: Refractory materials can withstand high temperatures. Refractory bricks are used in lining furnaces, kilns, fireboxes, and fireplaces. They are made by mixing MgO and clay.

Q92. The electronegativity of the [1]A element first decreases and then increases. This behavior is due to poor shielding of:

• A. S electron
• B. p - electron
• C. d- electron✓
• D. f - electron

Explanation: Electronegativity is the tendency of an atom to attract electrons. As we go down from top to bottom in group 1, more electron shells are added. As new shells are added, the ability of the nucleus to attract electrons decreases, and since the distance between the nucleus and the outer shell increases, the electromagnetic force decreases. As we move further down the group, more electrons are added to the d orbitals. Increased electron pair repulsion occurs, which implies that the electrons in these respective orbitals impart a poor shielding effect.

Q93. Sodium tetrabora e Na2B4O7.10H2O is

• A. Colemanite
• B. Borax✓
• C. Diaspore
• D. bauxite

Explanation: The given formula, Na2B4O7.10H2O is that of borax.

Q94. 2.41 (s) + NaOH (aq) + 2H2O ------- 2NaAlO2 + 3H2 The above reaction is slow at the start but speeds up after some time. This is because of:

• A. The reaction is exothermic and the heat generated speeds up the reaction
• B. The hydrogen liberated during the reaction acts as a catalyst
• C. The protective oxide layer of the aluminum dissolves and the meal surface is exposed to the reactant✓
• D. Sodium aluminate is highly soluble; therefore, it helps the reaction move in the forward direction

Explanation: Aluminium has a protective coat, due to which it initially reacts slowly. After a while, this coat dissolves, causing the reaction to speed up due to the increased exposed surface area of aluminum. The generation of heat increases the temperature. So if the reaction was exothermic, an increase in temperature would cause the reaction to move in a backward direction. A catalyst cannot be consumed or produced in a reaction, and hydrogen gas is being produced here, so it cannot be a catalyst. Solubility is not related to the speed of reaction.

Q95. Sodium carbonate, when fused with sand, forms sodium silicate, which is commonly known as

• A. Soda glass
• B. Water glass✓
• C. Jinna glass
• D. Pyrex glass

Explanation: Sodium silicate is commonly known as water glass, or soluble glass. It gets its name because it is essentially glass (silicon dioxide) in water. As the water evaporates, the solution solidifies into a glassy solid. It's formula is Na2SiO3. Soda glass is a mixture of Na2SiO3 and CaSiO3. There is no such thing as Jinna glass. Pyrex glass was originally made of borosilicate glass, which is very resistant to thermal shock. Currently, Pyrex is made of soda-lime glass. It can withstand abrupt changes in temperature and does not break on heating.

Q96. Silicones are resisted to chemical attack and are used as

• A. Painta✓
• B. Venshes
• C. Water proofing fabrics
• D. All of the above

Explanation: Silicon is used in Paints as it improves adherence, waterproofing and resistance to chemicals.

Q97. Select the oxide, which is in the solid state at room temperature:

• A. N2O5✓
• B. N2O
• C. NO2
• D. N2O3

Explanation: N2O5 is solid at room temperature.

Q98. Group 5th elements arsenic and antimony are considered as:

• A. metallic
• B. Non-metallic
• C. metalloids✓
• D. transition elements

Explanation: These two are Metalloids because they do not conduct electricity but are metals.

Q99. The formula for mustard gas is:

• A. (C2H2Cl2)2S
• B. (C2H4Cl2)2S
• C. (C2H3Cl2)2S
• D. (C2H4Cl)2S✓

Explanation: (C2H4Cl)2S is the formula for mustard gas.

Q100. All gases below are monoatomic except:

• A. H✓
• B. He
• C. Ne
• D. Xe

Explanation: Hydrogen is a diatomic gas, as its molecule has two H atoms.

Q101. Choose the correct name of Ba₂XeO:

• A. Barium Xenate
• B. Barium Xenthate
• C. Barium Prexenate
• D. Barium Perxenthate✓

Explanation: The correct name for Ba2Xe is Bareium Perxenthate.

Q102. The electronic configuration of Cu(29) is:

• A. -3s2 3p6 3d10 4s1✓
• B. -3s2-3p 3d9 4s2
• C. -3s2-3p 3d8 4s2
• D. -3s2-3p 3d9 4s2

Explanation: Cu(29)= 1s2 2s2 2p6 3s2 3p6 4s1 3d10

Q103. The oxidation power of halogen depends upon:

• A. energy of dissociation
• B. electron affinity of atoms
• C. hydration energies of lons
• D. all of the above✓

Explanation: The halogens D are good oxidizers The oxidizing power of halogens in an aqueous medium depends on their electron affinity, bond dissociation energy, and heat of hydration.

Q104. All compounds are organic except

• A. (H₂N)2CO
• B. NH4 CNO✓
• C. CH₂NO₂
• D. H₂N₂HSO4

Explanation: Ammonium cyanate does not contain any C-H covalent bonds, so it is not an organic compound.

Q105. The oxidation number of cobalt in [Co(en)2H2O(CN)]2+:

• A. 2
• B. 3✓
• C. 4
• D. 5

Explanation: The charge on EN is 0. The charge on the water is 0, the charge on CN is -1, and the charge on the complex is +2. For the central atom, consider that the oxidation number of Co is x. Therefore, the oxidation number of Co is +3.

Q106. Ammonium hydroxide was added to a salt solution, and a deep blue color was obtained. The solution contains ions of:

• A. Zn2
• B. Cu2✓
• C. Fe
• D. Ba+2

Explanation: Reaction is CuSO4+2NH4OH—---> (NH4)2SO4 +Cu(OH)2 The solution contains Cu2+ ions.

Q107. The color of coordination compound bisdimethylglyoxime nickel (11) is:

• A. red✓
• B. blue
• C. orange
• D. black

Explanation: Nickel bis(dimethyl glyoximate) is the coordination complex with a bright red colour.

Q108. Choose the compound tetraamine aqua chloro cobalt (III) chloride:

• A. Co(NH3)4H2O(Cl2-2)Cl3-3
• B. Co+2(NH3)4H2O(Cl2-2)Cl3-3
• C. Co(NH3)4H2O(Cl2-2)Cl3-3
• D. [Co(NH3​)4​(H2​O)Cl]Cl2✓

Explanation: Tetraammineaquachlorocobalt (III) chloride →[Co(NH3​)4​(H2​O)Cl]Cl2

Q109. The conversion of carbonate to urea is:

• A. Slow and exothermic
• B. Fasr and exothermic
• C. Slow and endothermic✓
• D. Fast and endothermic

Explanation: The formation of urea from carbonate is a slow and endothermic reaction.

Q110. Vehicular emissions, that are the major environmental concern, is

• A. CO2✓
• B. CO
• C. Low hydrocarbons
• D. All of them

Explanation: CO2 is the major vehicular emission responsible for causing the greenhouse effect and environmental pollution.

Q111. Tetraethyl lead (C2H2)4Pb is used as an antoknock agent and abandoned because of its hazardous product during the combustion of fuel. The hazardous product is

• A. CO2
• B. CO
• C. Lead✓
• D. Free radica ethyne (C2H2)

Explanation: TEL can cause chronic lead poisoning, and hence its hazardous product is lead.

Q112. Select the formula of 2-methyl pentane:

• A. C3H12
• B. C5H16
• C. C6H12
• D. C6H14✓

Explanation: The formula for 2-methyl pentane is C6H14.

Q113. In the reforming process, open-chain hydrocarbons are converted into:

• A. Polymers
• B. Branched-chain hydrocarbons✓
• C. Ring hydrocarbons
• D. Branched and ring hydrocarbons

Explanation: Reforming is also called AROMATIZATION and is a process in which open-chain hydrocarbons are converted into branched-chain hydrocarbons

Q114. An organic compound after fusion with sodium gives a white precipitate when concentrated nitric acid and then silver nitrate solution are added to the filtrate. The compound is likely to be

• A. CH3CH2CHO
• B. CH3CH2CH2OH
• C. CH3CH2COOH
• D. CH3CH2CH2Br✓

Explanation: This is called Lalaigne’s test, which is done for the detection of halogens. While all the other options given do not have halogens.

Q115. Ethyne has a total of:

• A. one sigma bond, two pi bonds
• B. one sigma bond, four pi bonds
• C. two sigma bonds, four pi bonds
• D. three sigma bonds, two pi bonds✓

Explanation: Hence ethyne has one sigma bond formed by carbon carbon over lapping and the other two sigma bonds are formed by carbon hydrogen overlapping while two pi bonds are formed by side to side overlapping of py and pz orbitals.

Q116. Choose the correct statement.

• A. Please bring litre of milk from nearest milk shop.
• B. Please bring a litre of milk from the nearest milk shop.✓
• C. Please bring a litre of milk from nearest milk shop.
• D. Please bring the litre of milk from the nearest milk shop.

Explanation: This option is correct. It uses the indefinite article "a" before "litre" and the definite article "the" before "nearest milk shop" to indicate a specific quantity and location.

Q117. carbon-carbon double bond as compared to a single bond is:

• A. Less susceptible to oxidation
• B. More susceptible to oxidation✓
• C. Equally susceptible to oxidation
• D. All of these

Explanation: A carbon-carbon double bond represents unsaturation, while a single carbon-carbon bond represents saturated hydrocarbons, alkanes that are generally unreactive; alkenes, on the other hand, are more reactive and hence more susceptible to oxidation than alkanes.

Q118. Which of the following is a nucleophil?

• A. AICI3
• B. CN✓
• C. H3O
• D. BF3

Explanation: AlCl3, H3O+ and BF3 are electrophiles, while CN is a nucleophile.

Q119. Select the most stable carbonium ion:

• A. +CH3
• B. +CH3CH₂
• C. (CH3)2 +CH
• D. (CH3)3C+✓

Explanation: Option D represents a tertiary carbonium ion, which is much more stable than primary or secondary carbonium ions.

Q120. Water is said to be permanently hard when it contains:

• A. carbonates of Ca2+ and Mg2+ ions
• B. Bicarbonates of Ca2+ and Mg2+ ions
• C. sulphates of Na+ and Mg2+ ions
• D. chlorides of Ca2+ and Mg2+ ions✓

Explanation: The presence of soluble salts of calcium and magnesium, i.e., sulfates and chlorides of calcium and magnesium, causes permanent hardness in the water.

Q121. A buffer solution containing H2CO3 and NaHCO3 is to be prepared to maintain a pH of 7.00. What must be the ratio NaHCO3 in order to realize such a pH if Ka of carbonic HCO3 acid is 4.3 x 107?

• A. 43
• B. 48
• C. 0.43
• D. 4.3✓

Explanation: pH=pKa+ Log NaHCO3/H2CO3 7=4.3*10^-7+ Log NaHCO3/H2CO3 Log NaHCO3/H2CO3=7 NaHCO3/H2CO3=10^7 NaHCO3=10^7* H2C03 NaHCO3=10^7*4.3^-7 NaHCO3=4.3

Q122. A sample containing aluminum weighing 10.0g yielded 2.0g of aluminum sulphide. What is the percentage of aluminum (atomic mass 27.0) in the sample? Sulphur (atomic mass 32.0) =

• A. 2.0 X 100/10✓
• B. 2.0/10 X 2 X 27/150 X 100
• C. 2.0/10 X 27/1500 X 100
• D. 2.0/10 X 150/3 X 27 X 100

Explanation: To find the percentage of aluminium in this sample, the following formula will be used: mass of aluminium in the sample =_ * 100 total mass of the sample 2 = _ * 100 10 Thus, Option 'A' is the correct answer.

Q123. Choose the region of the spectrum which would be used to determine the structure of crystalline solids:

• A. visible
• B. infrated
• C. X rays✓
• D. ultraviolet

Explanation: To determine the structure of crystalline solids, the spacing between the atoms of crystal (i.e. in the order of 10¹⁰ or degree angstroms Å) should correspond to the wavelength of the region of the spectrum used. Its wavelength is on the order of 10⁻¹² to 10⁻⁸.This wavelength range corresponds to the spacing between atoms of crystal. Thus, option C is correct.

Q124. The temperature at which domains of the ferromagnetic substance disorient is:

• A. critical temperature
• B. absolute temperature
• C. Curie Temperature✓
• D. normal temperature

Explanation: Ferromagnetic MATERIALS can be permanently magnetized. Curie Temperature: The temperature at which the ferromagnetic element starts to lose its magnetism and becomes paramagnetic. Understanding the above-stated facts, option ‘C’ is the correct answer.

Q125. .Which one of the following most closely resembles an ideal gas?

• A. Xe
• B. H2
• C. CO2
• D. He✓

Explanation: Helium is an inert gas that exists as a single atom, resulting in the lowest conceivable van der Waals dispersion forces. It occupies an approximately negligible volume and possesses a very tiny mass. It is also highly compressible. Because of all of these properties, helium is the most ideal gas. Properties of Ideal Gas: The particles of gas have negligible volume and mass. They are equally sized. They are compressible. They are always in motion, colliding elastically within a container with no energy loss. They take the shape of the container. They behave inertly, i.e., they do not have intermolecular forces.

Q126. According to molecular orbital theory, which of the following is most unstable molecule?

• A. He2+
• B. H2-
• C. H2+
• D. H2-2✓

Explanation: MOLECULAR ORBITAL THEORY: It states that all the atoms tend to combine together and form molecular orbitals. It is basically a method for describing the electronic structure of molecules using quantum mechanics. The number of electrons present in all four options is shown below : We know that, greater the number of electrons present in an atom, the more unstable it is. Here, H₂⁻² has the maximum number of electrons. Thus, it is most unstable.

Q127. How many grams of waster are produced in burning 2.24dm of hydrogen at STP?

• A. 180g
• B. 81g
• C. 1.8g✓
• D. 0.18g

Explanation: The solution for this question is given below:

Q128. 50 cm of KOH solution was titrated against 1.0M HCIusing phenolphthalein as an indicator. The acid used was found to be 7,5 cm. the concentration of KOH solution is:

• A. 0.15 M✓
• B. 1.5 M
• C. 0.75
• D. None

Explanation: The calculations are shown below : The chemical equation used in this titration is : HCl+KOH→KCl+H₂O In this chemical reaction, the molar ratio between HCl and KOH is 1:1. So, moles of HCl = moles of KOH Mʜᴄʟ × Vʜᴄʟ = Mᴋᴏʜ × Vᴋᴏʜ Mʜᴄʟ × Vʜᴄʟ ----------------- = Mᴋᴏʜ Vᴋᴏʜ (placing values) 1 × 7.5 ------------ = Mᴋᴏʜ 50 Mᴋᴏʜ = 0.15M

Q129. Choose the least inert gas:

• A. Helium
• B. Neon
• C. argon
• D. Xenon✓

Explanation: All of the noble gases are completely inert except for xenon. Under normal conditions, xenon is non-reactive, but at extreme temperatures and pressures, it covalently bonds to fluorine, oxygen, nitrogen, and carbon. Three fluorides of xenon are known: XeF2, XeF4, and XeF6 Although it has a complete outer shell, due to its highly reactive behavior, xenon is considered the least inert gas. Thus, Option ‘D’ is correct.

Q130. Uranium-235 decays to thoriun+ 234 by the process of

• A. fission
• B. beta decay
• C. alpha radiation✓
• D. gamma radiation

Explanation: URANIUM-238 : Mass number : 238 Atomic number : 92 THORIUM-234 : Mass number : 234 Atomic number: 90 From above, it is clear that mass number decreases by 4 and atomic number decreases by 2. That’s exactly what happens in alpha decay so option ‘C’ is the right answer.

Q131. The hydrolysis of an ester proceeds most slowly under the conditions of:

• A. high acidity
• B. high basicity
• C. neutrality✓
• D. high temperature

Explanation: An ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group (−OH) is replaced by an alkoxy group (−O−R). The hydrolysis of esters is catalyzed by either an acid or a base. The first step involved in this reaction is the breakage of the C=O bond . In case of an acid, the proton from the acid attacks on it and breaks it and in case of base, a hydroxide ion attacks and forms a new species. In a neutral solution, there is no species to break the bond. Thus, in a neutral solution, the hydrolysis is too slow, and as a result, it is normally avoided.

Q132. If an atom exists in the excited state n = 5, the maximum number of transitions that take place are:

• A. 6
• B. 5
• C. 10✓
• D. 3

Explanation: To solve such a question, here’s an amazing trick! We know that n is 5. Step 1: From the ‘n’ value, start counting backwards. i.e. 5 4 3 2 1 Step 2 : Now drop the ‘n’ value and add the rest of the numbers, i.e. 4+3+2+1 = 10 That’s your answer!

Q133. Which one of the following is strongest acid?

• A. FCH COOH✓
• B. CH3COOH
• C. CICH COOH
• D. C6H5CH,COOH

Explanation: Electronegativity increases the acidity by increasing the ionic character of O-H. Electronegativity decreases in the order F > Cl > Br, and hence the acidic effect also decreases in the same order. Here and overall, fluorine is the most electronegative element. Thus, it is most acidic.

Q134. The situation in which the excited state i.e. metastable state contains morestate,i.e., thestate, electrons than the ground is called:

• A. ionized state
• B. stimulations
• C. population inversion✓
• D. all of these

Explanation: GROUND STATE: The ground state of an electron, the energy level it normally occupies, is the state of lowest energy for that electron. METASTABLE STATE: It is a particular excited state of an atom that has a longer lifetime than the ordinary excited states and that generally has a shorter lifetime than the ground state. Population inversion occurs when more electrons in a particular situation are in a higher-energy state than in a lower-energy state. Hence, option C is correct.

Q135. Which one of the following would you suggest to locate the position of the double bond between carbon atoms in an organic compound?

• A. Addition of bromine water
• B. Addition of HI
• C. Oxidation with ozone✓
• D. All of the above

Explanation: Ozonolysis, i.e., oxidation with ozone, is the method used to point out the position of a double bond in an organic compound. Thus, option ‘C’ is the correct answer.

Q136. Most of the oxides of non-metals combine with water to form:

• A. hydrogen gas
• B. salt and water
• C. a base
• D. An acid✓

Explanation: Non-metals are the elements that form negative ions by accepting or gaining electrons. Oxides of non-metals combine with water to form acids. For example, sulfur and nitrogen are non-metals. Their oxides are sulfur dioxide and nitrogen oxide, respectively. When they combine with water, they form sulfuric acid and nitric acid. These are responsible for acid rain.

Q137. In which of the following atoms, the Is orbital is the smallest in size?

• A. bromine
• B. chlorine
• C. fluorine
• D. iodine 200✓

Explanation: For all elements in general, the higher the atomic number, the smaller the 1s orbital. The 1s orbital is closest to the nucleus. Therefore, it is mostly in the nucleus’s positive electrostatic field. The greater the atomic number, the greater the number of electrons in the outer shells, and thus, the greater the electrostatic force between the nucleus and electrons. Now, among all the halogens, iodine has the highest atomic number (127). Thus, the first orbital of iodine is the smallest.

Q138. The highest oxidation state of manganese-3s72 3p 3d5+4S2 in its compounds is:

• A. +2
• B. +5
• C. +7✓
• D. +8

Explanation: The highest oxidation state of manganese in its compounds is +7. In this oxidation state, manganese forms compounds like potassium permanganate (KMnO4), which is a powerful oxidizing agent commonly used in various chemical processes and laboratory applications.

Q139. The bleaching action of bleaching powder is due to "available chlorine". It is the amount of chlorine

• A. that is required for the preparation of bleaching powder
• B. site free when excess of sulphuric acid is added to the bleaching powder
• C. that is required for the generation of hypochlorine✓
• D. Both B and C

Explanation: The bleaching action of bleaching powder is due to the release of "available chlorine" when it comes into contact with an acidic substance, like sulfuric acid. When bleaching powder (calcium hypochlorite, Ca(ClO)2) is treated with an acid, it decomposes to release hypochlorous acid (HClO) and calcium sulfate (CaSO4). Hypochlorine acid is the active bleaching agent responsible for its bleaching properties.

Q140. The angle subtended at the centre of a sphere by its surface area is equal to:

• A. 4/3 π radian
• B. 4/3 π steradian
• C. 4 π radian
• D. 4 π streradian✓

Explanation: One steradian is the solid angle of a sphere subtended by a portion of the surface whose area is equal to the square of the sphere’s radius. The complete surface area of a sphere= 4πr² so the total solid angle about a point = 4πr²/r² = 4π steradian The steradian is the unit of solid angles. It is used in 3D geometry. Whereas the radian is used in planar geometry so options A and C are ruled out as we are dealing with a 3D cone here. (The mention of surface area in the question implies that 3D geometry is involved)

Q141. MLT are are the dimersions of

• A. strain
• B. refractive index
• C. magnification
• D. All of these✓

Explanation: The given dimensions indicate a dimensional quantity. Strain = change in length/original length [L]/[L] =1 so it is dimensionless Refractive index = velocity of light in medium 1/ velocity of light in medium 2 [LT-1]/[LT-1]=1 so it is dimensionless Magnification=Image length/ Object length [L]/[L] = 1 so it is dimensionless As all these quantities have no dimensions, option D is correct.

Q142. The magnitude of the resultant of two forces is 2F. If the magnitude of each force is F. Than the angle between these forces is:

• A. 0°✓
• B. 90°
• C. 120°
• D. 180°

Explanation: Both vectors have the same magnitude, F, and the resultant is F+F = 2F. If two vectors have the same direction, then the resultant vector is the algebraic sum of the two vectors, as in this case. The vectors must therefore also have the same direction, making the angle between them 0°. The resultant is at it's greatest value when the angle between the vectors is 0°. Options B and C are incorrect, as in these cases their resultant would be a value less than 2F. Option D is incorrect as vectors are in opposite directions when angle between them is 180° so the resultant is the algebraic difference between the two, F-F = 0.

Q143. Axis equal to:

• A. 4
• B. Zero✓
• C. 2
• D. 1

Explanation: From the given diagram: i x j= k j x k= i k x i= j j x i = -k k x j= -i i x k= -j Now to solve the given expression, k x j= -i so j x -i = 0 , since these two vectors are perpendicular and the dot product of two perpendicular vectors is 0.

Q144. Three vactors of equal magnitude are acting on the three sides of an equilateral triangle. The magnitude of their resultant is:

• A. zero✓
• B. 3
• C. √3
• D. 1.73

Explanation: The three vectors act as shown in the diagram above. According to the head-to-tail rule, the resultant is obtained by joining the head of the last vector to the tail of the first vector. Therefore, the resultant vector obtained is zero.

Q145. The physical quantity that produces angular acceleration in the body is:

• A. Force
• B. Moment of inertia✓
• C. Impulse
• D. Torque

Explanation: Torque is a measure of the force that can cause an object to rotate about an axis. Force is what causes an object to accelerate in linear motion, while torque is what causes an object to acquire angular acceleration. The moment of inertia is a quantity expressing a body's tendency to resist angular acceleration. Impulse quantifies the effect of force acting over time to change the momentum of an object.

Q146. The point at which an applied force produces linear motion but no rotatory motion is:

• A. mid-point
• B. center of gravity✓
• C. optical centre
• D. pole

Explanation: The center of gravity is where the entire mass of an object is concentrated. When a force is applied to the center of gravity of a body, it undergoes linear motion and moves in a straight line; however, no rotation occurs.

Q147. A ball is thrown vertically upward with a velocity of 98 m/s. if it takes 10 seconds to reach the highest point then the acceleration of the ball is:

• A. 9.8 m/s²
• B. 980 m/s
• C. 98 m/s²
• D. -9.8 m/s✓

Explanation: Using the first equation of motion: v = u + at final velocity(v) =0m/s initial velocity (u) =98m/s time (t) = 10 acceleration (a) = ? 0=98+10a -98=10a a=-9.8m/s²

Q148. A man throws a ball vertically upward in a compartment of an accelerated train. The ball will fall:

• A. in front of him
• B. in his hand
• C. behind him✓
• D. beside him

Explanation: When the ball is thrown upwards by the man, it has horizontal velocity v, the same as the man who is present in the moving train. Once the ball is thrown upwards, it acts as a freely falling body, and it's horizontal velocity remains constant. Meanwhile, because the train is accelerating, the horizontal velocity of the man increases. The horizontal displacement of the man is therefore greater than that of the ball. So when the ball falls back to the ground, it's position is behind the man, and it lands behind the thrower.

Q149. A bomber drops a bomb, when it is vertically above the target. It misses the target because of:

• A. vertical component of the velocity of bomber
• B. force of gravity
• C. acceleration of the bomber
• D. horizontal component of the velocity of bomber✓

Explanation: When the bomber drops the bomb, it acts as a projectile and has both horizontal and vertical components of velocity. At the exact moment of release, the horizontal speed of the bomb is the same as that of the bomber plane that released it. The vertical speed is zero. The vertical speed changes along the path at the rate of acceleration due to gravity, whereas the horizontal velocity remains constant. This horizontal velocity causes the bomb to move in a curved path that starts flat and level but curves downward to strike the ground at an angle. Therefore, if the bomb is released directly above the target, it will miss it due to the horizontal velocity, which causes it to move forward.

Q150. The property of the moving object by virtue of which it exerts force on the object that tries to slop it is:

• A. inertia of the body✓
• B. quantity of motion in the body
• C. Acceleration of body
• D. All of these

Explanation: Inertia means resistance to change. It is the property of the body by virtue of which it cannot change by itself its state of rest or of uniform motion unless an unbalanced external force acts on it. The quantity of motion is called momentum. Momentum and acceleration do not try to stop a body; they are only used to describe motion, so only option A is correct.

Q151. The dot product of force and velocity is equal to:

• A. power✓
• B. impulse
• C. couple
• D. Momentum

Explanation: Velocity=distance/time Force x velocity can also be written as force x distance or time force x distance = work done so the formula can be written as Work done/time, which is the formula for power, Impulse = force x time Couple = force x distance Momentum = mass x velocity

Q152. The escape velocity from the earth gravitational field depends upon:earth's

• A. rotation of earth
• B. mass of body
• C. radius of earth✓
• D. mass of earth

Explanation: Escape velocity, Ve​ =√( 2GM/R) Acceleration due to gravity, g= GM/R², which is always constant. Plugging this value of g in the first equation: Ve= √2gR , where R is the radius of the earth . From the above equation, we see escape velocity is dependent upon is gravitational acceleration and radius of the earth so option C is correct.

Q153. If the velocity of a body becomes half, the kinetic energy of the body will become:

• A. one fourth✓
• B. double
• C. four times
• D. half

Explanation: Kinetic energy=1/2mv² where m is mass of body and v us it's velocity so kinetic energy is directly proportional to v² So if velocity is reduced by ½ then kinetic energy is reduced by (½)²=¼ so kinetic is reduced by one fourth.

Q154. The angular velocity for the daily rotation of the earth is

• A. π/3 radian hr-1
• B. π/6 radian hr-1
• C. π/12 radian hr-1✓
• D. 12 radian hr-1

Explanation: The angular velocity (ω) is the scalar measure of rotation rate. In one complete rotation, angular distance travelled is 2π and time is time period (T). Angular velocity is given by the following formula: ω=2π/T The time period for one complete rotation of the Earth is 24 hours so ω=2π/24 =π/12

Q155. The weight of a pilot when diving down in a jet plane with an acceleration of 9.8m/s2 will become

• A. Double
• B. Half
• C. Negative
• D. Zero✓

Explanation: Weight of pilot = Original Weight + Apparent Weight = mg+(-ma) a= 9.8ms-2 So weight of pilot = 0

Q156. The Geostationary satellites are

• A. stationary
• B. Rotating with the speed of earth✓
• C. rotating very fastly
• D. rotating very slowly

Explanation: Geostationary satellites remain at the same position with respect to the Earth, so that they scan the same place in a better way. Therefore, the relative velocity of geostationary satellite with respect to the spinning motion of the Earth is 0 m/s.

Q157. ML-1T-1 are the dimension of

• A. angular momentum
• B. power
• C. impulse
• D. viscosity✓

Explanation: The dimensions ML-1T-1 indeed correspond to viscosity. The correct explanation for option D is as follows:Viscosity is a property of fluids that measures their resistance to flow. It determines how easily a fluid can be deformed under the influence of shear stress. The dimensions ML-1T-1 represent viscosity, where:M represents massL represents lengthT represents time In the context of the dimensions ML-1T-1, viscosity is proportional to mass divided by the product of length and time. This indicates that viscosity involves the interactions between mass, length, and time in the context of fluid flow.

Q158. A two meter high tank is full of water.. A hole is made in the middle of tank. The speed of effect is

• A. 4.9 ms-1
• B. 9.8 ms-1
• C. 4.42 ms-1✓
• D. 3.75 ms

Explanation: 4.42ms-1 v= ( under root)2gh Middle of tank = half of total = 1 m

Q159. The quantity which specifies the displacement as well as the direction of motion in Simple harmonic motion is

• A. Phase angle
• B. Angular frequency
• C. Path difference
• D. Amplitude✓

Explanation: Amplitude specifies displacement and direction of SHM.

Q160. The magnitude of the periodic force, which is the simple pendulum exerts on the suspension point, depends upon

• A. length of the pendulum✓
• B. time period of vibration of pendulum
• C. mass of the bob of pendulum
• D. value of 'g'

Explanation: Periodic force depends only on the length of a simple pendulum.

Q161. When the pressure in the medium increases, the speed of sound in that medium:

• A. decreases
• B. increases
• C. does not change✓
• D. sometime decreases, some time increases

Explanation: Speed of sound does not depend on pressure of gas.

Q162. The number of loops in stationary waves depends upon:

• A. velocity of waves
• B. wavelength of waves
• C. nature of the medium
• D. frequency of waves✓

Explanation: No. of loops in stationary waves depend on frequency of waves.

Q163. When the light passes from air to glass, it suffers a change in the

• A. wavelength of light
• B. speed of light
• C. frequency of light
• D. Both A and B✓

Explanation: Both the wavelength and speed of light change when light passes from air to glass.

Q164. When the light is moving from rare medium to denser medium on reflection it suffers a phase change of:

• A. 180°✓
• B. 120°
• C. 90°
• D. 0°

Explanation: When a light wave passes from a rarer medium to a denser medium, there will be a phase change of 180°.

Q165. We can hear sound around the corner but cannot see because of:

• A. interference
• B. diffraction✓
• C. polarization
• D. dispersion

Explanation: The diffraction of sound waves around a corner is noticeable. Therefore, sound can be heard around corners but cannot be seen.

Q166. The powers of the objective and eye piece of telescope are 0.5 diopter and 10 diopter respectively. The magnifying power of telescope is:

• A. 0.5
• B. 10
• C. 20✓
• D. 0.05

Explanation: Magnifying power of telescope = focal length of objective/focal length of eyepiece = power of eyepiece/ power of objective Power of objective = 0.5 D Power of eyepiece = 10 D Magnifying Power of telescope = power of eyepiece/ power of objective = 10/0.5 = 20

Q167. At constant temperature when the volume of the given mass of gas is doubled its density becomes:doubled,temperature,At a

• A. double✓
• B. one fourth
• C. four times
• D. half

Explanation: At constant temperature, if the pressure of the gas is doubled, the density is also doubled.

Q168. The process adlabalic processthat is performed quickly is:

• A. isobaric process
• B. adlabalic process✓
• C. isothermal process
• D. isochoric process

Explanation: The adiabatic process is performed quickly when the system is perfectly insulated from the surrounding environment.

Q169. For all irreversible process, the entropy of the system:

• A. decreases
• B. remains constant
• C. is zero
• D. increase✓

Explanation: The entropy of the universe increases in an irreversible process, such as the transfer of heat from a hot object to a cold object.

Q170. The wave nature of an electron is illustrated by

• A. photoelectric effect
• B. compton effect
• C. penetrating effect
• D. diffraction✓

Explanation: The wave nature of an electron is illustrated by its electron diffraction, as explained by davisson germer experiment.

Q171. The potential gradient between two charged plates having separation of 0.5cm and a potential difference of 12 volts is:

• A. 240 NC-1
• B. 24 NC-1
• C. 2.4 NC-1
• D. 2400 NC-1✓

Explanation: As we know, Potential gradient is given by E= -dV/dR So, 12/0.005 = 2400 V/m= 2400 N/C

Q172. Ohm X Farad is equivalent to

• A. second✓
• B. weber
• C. henry
• D. tesla

Explanation: Ohm is the unit of resistance equal to Volt/Ampere, while farad is the unit of capacitance equal to Coulomb/Volt; hence, Ohm*farad is equal to second, VOLT/AMPERE*COULOMB/VOLT=COULOMB/AMPERE=Q/I=T.

Q173. A wir of uniform cross section A, length I and resistance R is cut into two equal pieces. The resistivity of each piece will be

• A. the same✓
• B. one fourth
• C. double
• D. one half

Explanation: Resistivity remains constant, it is a constant value.

Q174. Two metallic conductors have the same value of resistivity. These conductors can be differentiated from the values of their:

• A. temprature coefficient✓
• B. resistances
• C. conductance
• D. conductivity

Explanation: Temperature coefficient is the property that enables to differentiate between materials of same resistivity, as all the other options indicate values that will be same for both the metallic conductors having same resistivity.

Q175. The total driving force of a battery to draw current through a circuit is called:

• A. voltage of battery
• B. power of battery
• C. e.m.f of battery✓
• D. all of these

Explanation: EMF is the source of voltage in a battery responsible for flow of charges through a circuit.

Q176. Two metallic wires lying parallel, If the current in these wires is flowing in the same direction, the wires will

• A. attract each other✓
• B. repel each other
• C. have no force of attraction or repulsion
• D. remain stationary

Explanation: Parallel wires with current in the same direction exert attractive forces on eachother.

Q177. The SI unit of magnetic flux is Weber, which is equal to:

• A. NmA-1✓
• B. Nm2 A-1
• C. NAm-¹
• D. NmA-2

Explanation: The unit of magnetic flux is Weber, which is equal to J/A, which is then equal to Nm/A-1.

Q178. If an electron and a proton are projected with the same velocity normal to a magnetic field, which one will suffer greater deflection?

• A. proton
• B. electron✓
• C. both will suffer greater defection
• D. None of these

Explanation: The deflection is inversely proportional to mass, so for an electron and a proton moving with the same velocity, an electron with lighter mass will deflect more, while a proton with heavier mass will deflect less.

Q179. The motional e.m.f depends upon:

• A. strength of magnetic field
• B. length of conductor
• C. speed of conductor
• D. all of these✓

Explanation: When a conductor is moved across a magnetic field, emf appears across its ends, known as motional emf. It is given by MOTIONAL emf = VBLsinQ; hence, all of the options are correct as factors on which motional emf depends.

Q180. voltxsecond is equal to:

• A. gauss
• B. weber
• C. henry✓
• D. tesla

Explanation: Henry is the unit of inductance, which is equal to 1 volt*sec/ampere, which is the voltage across a conductor directly proportional to the rate of change of current.

Q181. The counter torque produced in the moving coil of generator is called:

• A. resotoring torque
• B. defelection torque
• C. back motor effect
• D. all of these✓

Explanation: When the current I passes through the coil, the coil experiences torque, which rotates the coil through an angle alpha. Due to deflection, suspension wire twist gives the restoring force; if the restoring force is CQ while the deflection torque is BIAN Cos alpha, then BIAN Cos alpha=CQ. Hence, all of the options represent the same counter torque produced in the generator.

Q182. The inductive reactance has an inductance of:

• A. 94.2
• B. 1.57
• C. 157✓
• D. 9,421

Explanation: Inductive reactance is the opposition offered by the inductor in the AC circuit to the flow of AC current. Inductive reactance= = wL = 2pifL = 2*3.14*50*0.5= = 157 ohm

Q183. In RLC series circuit when the frequency of AC source is very low, the circuit an:

• A. resistive circuit
• B. capacitive circuit✓
• C. inductive circuit
• D. resonant circuit

Explanation: At low frequencies, the series circuit is capacitive as Xc>Xl, but at higher frequencies, the series circuit is inductive as Xl>Xc. With the decrease in frequency, it becomes more capacitive, i.e., the current decreases, and it changes from inductive to capacitive.

Q184. Which of the following makes the motion of a perpetual motion machine a physical impossibility?

• A. fist law of thermodynamics
• B. second law of thermodynamics✓
• C. third law of thermodynamics
• D. None of these

Explanation: As the second law of thermodynamics states, the more energy is transformed, the more is wasted. And for a perpetual motion machine to work, it has to have the energy that was never wasted, which makes it a physical impossibility.

Q185. The process of combining low frequency signal with high frequency carries waves is called:

• A. rectification
• B. amplification
• C. modulation✓
• D. magnification

Explanation: Modulation is the process of combining low-frequency signals with high-frequency carrier waves to convert data into radio waves. While rectification is the conversion of AC current into DC current, amplification simply means.

Q186. The ratio of volumetric strain to volumetric stress called:

• A. compressibility✓
• B. young's modulus
• C. bulk's modulus
• D. shear's modulus

Explanation: Compressibility is the ratio of volumetric strain to volumetric stress. It is the inverse of bulk's modulus. Its SI unit is the pascal. Strain: A force tending to pull or stretch something to an extreme or damaging degree Stress is a quantity that describes the magnitude of the forces that cause deformation (strain).

Q187. The substance that undergoes plastic deformation until it breaks is:

• A. ductile substance✓
• B. brittle substance
• C. plastic substance
• D. all of these

Explanation: The substance which undergoes plastic deformation until it breaks is a DUCTILE SUBSTANCE. Therefore, option 'A' is correct.

Q188. The process by which the potential barrier of the deplection region can be increased or decreased is called:

• A. Amplification
• B. Biasing✓
• C. Modulation
• D. Doping

Explanation: Biasing is the application of DC voltage to set up certain operating conditions. It either increases or decreases the strength-barrier potential of the junction. A forward bias reduces the strength of the potential barrier, whereas a reverse bias strengthens the potential barrier. This corresponds to the statement of the question, and thus option B is the correct option.

Q189. The color of light emitted by light emitting diode depends upon:

• A. forward voltage
• B. reverse current
• C. forward current
• D. type of semiconductor✓

Explanation: LEDs are semiconductors that convert electrical energy into light energy. The color of the emitted light depends on the type of semiconductor material. Depending on which LEDs can be classified into three wavelengths: ultraviolet, visible, and infrared, Among the above options, options ‘A, ‘B, and C’ have nothing to do with the color of light emitted by LEDs. Therefore, they are eliminated.

Q190. The combination of AND and NOT gates is called:

• A. NAND gate✓
• B. NOR gate
• C. OR gate
• D. XOR gate

Explanation: A NAND gate is a combination of AND and NOT gates. Option ‘A’ corresponds to the statement of the question.

Q191. If the temperature of the black body doubles, the intensity of radiation from it will become:

• A. double
• B. four times
• C. six times
• D. sixteen times✓

Explanation: BLACK BODY: A blackbody is a theoretical or model body that absorbs all radiation falling on it, reflecting or transmitting none. It is a hypothetical object that is a “perfect” absorber and “perfect” emitter of radiation over all wavelengths. Stefan-Boltzmann Law: It relates the total energy emitted (E) to the absolute temperature (T). E ∝ T⁴ We know that the intensity of the radiation from a black body is directly proportional to its energy. Thus, it can be concluded that if we increase the temperature of the black body by 2 (i.e., we double it), the intensity increases by 2⁴ i.e. it increases 16 times). Thus, option ‘D’ is the correct answer.

Q192. The scattering angle for which the Compton shift in wavelength is equal to Compton wavelength is:

• A. 0=90°✓
• B. 0=0"
• C. 0=45°
• D. 0=180°

Explanation: COMPTON’S EFFECT: It is the scattering of a high-frequency photon after a collision with an electron, which results in a decrease in the wavelength of the photon. The change in wavelength is called Compton’s shift and is given by: λ′−λ=hmₒc(1−cosθ). The factor hmₒc is known as compton’s wavelength. The compton’s shift and compton’s wavelength will be equal when the factor (1−cosθ) is equal to 1. Now cos should be equal to 1, and for that, θ should be 90°. Thus, option ‘A’ is the right answer.

Q193. The uncertainty in energy of a photon that is emitted from an atom radiating for 10 seconds is:

• A. 4x10 joul
• B. 4x107 ev✓
• C. 6.6x10 ev
• D. 4x10 joul

Explanation: HEISENBERG’S UNCERTAINTY PRINCIPLE : The uncertainty in the energy (ΔE) times the uncertainty in the time (Δt) is greater or equal to planck’s constant (h). i.e ΔE . Δt = h h ΔE = --- Δt (placing values) 6.62 × 10⁻³⁴ ΔE = ----------------- 1 × 10⁻⁸ ΔE = 6.62 × 10⁻²⁶ Joules 6.62 × 10⁻²⁶ ΔE = ------------------ 1.6 × 10⁻¹⁹ ΔE = 4 × 10 ⁻⁷ eV

Q194. When the voltage of the target in the X-ray tube increases, then the

• A. penetrating power of x-ray increases
• B. intensity of x-rays increases✓
• C. wavelength of x-rays increases
• D. all of these

Explanation: X-RAY TUBE: An X-ray tube is a vacuum tube that converts electrical input power into X-rays. The increase in x-ray tube voltage increases the amount of radiation coming out, i.e., the intensity of X-rays increases. Also, the average photon energy increases (i.e., the wavelength decreases).

Q195. The frequency of light having wavelength 3×10 cm is

• A. 1x10
• B. 3.0x107
• C. 1x10¹0
• D. 1x1013✓

Explanation: We know that v = f λ v --- = f λ (placing values) 3 × 10⁸ f = ------------------ 3 × 10⁻³ × 10⁻² f = 1 × 10¹³

Q196. When a radioactive atom decays and its mass number decreases by 4 and charge number decreases by 2, the atom will emit

• A. Alpha radiation✓
• B. Beta radiation
• C. Gamma radiation
• D. X radiation

Explanation: Alpha radiations are doubly positively charged helium nuclei. When such radiation is emitted from a radioactive element, its mass number decreases by 4 and its atomic number decreases by 2.

Q197. One disintegration per second is equal to

• A. one curie
• B. one Becquerel✓
• C. one half life
• D. all of these

Explanation: In radioactivity, activity is defined as disintegrations per second. The SI unit of Activity is Becquerel (Bq). Thus, 1 disintegration per second is equal to 1 Bq.

Q198. A fission reaction can be produced by:

• A. fast neutrons✓
• B. slow neutrons
• C. thermal neutrons
• D. all of these

Explanation: Fission occurs when a neutron bumps into a larger atom, forcing it to excite and split into two smaller atoms, known as fission products. Elements with odd atomic masses are more fissile (prone to fission) because the extra neutron adds the energy required to fission the resulting nucleus. U-238 has even more atomic mass. Thus, because of the large amount of energy needed, U-238 can only undergo fission when fast-moving neutrons strike it.

Q199. The correct expression for the coulomb's force is:

• A. F-1=1/4πe0 x q1q2/r2 x r
• B. F = 1/4πe0 x q1q2/r2 x r✓
• C. F-1 = 1/4πe x q1q2/r2 x r
• D. F = 1/4πe x q1q2/r2 x r

Explanation: According to the expression of coulomb’s law, the magnitude of Coulomb’s force is directly proportional to the product of two point charges and inversely proportional to the square of the distance between them.

Q200. In oogamy, fertilization involves:

• A. A small non­-motile female gamete and a large motile male gamete
• B. A large non-­motile female gamete and a small motile male gamete✓
• C. A large non-­motile female gamete and a small non­motile male gamete
• D. A large motile female gamete and a small non­-motile male gemete

Explanation: Oogamy is the sexual reproduction involving the formation and subsequent fusion of a large, usually stationary, non-motile, female gamete and a small motile male gamete. The female gamete may contain nourishment for the development of the embryo, which is often retained and protected by the parent organism. A. Female gamete is large not small and male gamete is small, not large. C. Female gamete is non motile but male gamete is motile. D. Female gamete is non motile and male gamete is motile.