MDCAT 2019

MDCAT 2019 Past Paper with Answers (All Subjects)

151 MCQs from MDCAT 2019 in our bank, each with its correct answer and a solution. This is a recall-based collection gathered from students and past-paper books, not the complete official paper.

MDCAT 2019 by subject

Biology

1.The protein coat of virus is called: (UHS MDCAT 2019)

  1. Capsid
  2. Cosmid
  3. Capsomere
  4. Chromophore
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Correct answer: (a) Capsid

The protein coat of a virus is its capsid.

2.Among followings, ______ enzyme is naturally found in human immunodeficiency virus (HIV). (UHS MDCAT 2019)

  1. Ligase
  2. Reverse Transcriptase
  3. RNA Polymerase
  4. DNA Polymerase
Show answer

Correct answer: (b) Reverse Transcriptase

Reverse transcriptase is carried in the virion and copies its RNA into DNA.

3.How many molecules of ATP would be utilized for phosphorylation of one glucose molecule during glycolysis? (UHS MDCAT 2019)

  1. Three
  2. Two
  3. Four
  4. One
Show answer

Correct answer: (b) Two

Two ATP are spent in phosphorylating the glucose before any is made.

4.Glycolysis takes place in the ______ of cells. (UHS MDCAT 2019)

  1. Nucleus
  2. Mitochondria
  3. Golgi complex
  4. Cytoplasm
Show answer

Correct answer: (d) Cytoplasm

Glycolysis needs no organelle and goes on in the cytoplasm.

5.If water has a high latent heat of vaporization, how could this property of water be helpful to plants and animals? (UHS MDCAT 2019)

  1. With the release of large amount of water, a small amount of heat loss can take place.
  2. With the release of small amount of water vapours, a great amount of heat loss can take place.
  3. It will keep their temperature very high.
  4. No cooling effect, with the release of even a large amount of water vapours.
Show answer

Correct answer: (b) With the release of small amount of water vapours, a great amount of heat loss can take place.

A little sweat carries off a great deal of heat, which is what makes evaporation such an efficient coolant.

6.Starch is present in tubers, fruits, and grains but absent in animal cells. Instead, animals have a substance stored in liver and muscles known as: (UHS MDCAT 2019)

  1. Galactose
  2. Glucagon
  3. Glycogen
  4. Glucose
Show answer

Correct answer: (c) Glycogen

Glycogen is the storage polysaccharide of liver and muscle.

7.Which is an example of a Disaccharide? (UHS MDCAT 2019)

  1. Starch
  2. Lactose
  3. Fructose
  4. Glycogen
Show answer

Correct answer: (b) Lactose

Lactose is glucose joined to galactose.

8.The covalent bond or bridge between two monosaccharides to form a disaccharide is called a: (UHS MDCAT 2019)

  1. Hydroxyl bond
  2. Hydrogen bond
  3. Carboxyl bond
  4. Glycosidic bond
Show answer

Correct answer: (d) Glycosidic bond

The link between two sugar units is a glycosidic bond.

9.The structure of a fibrous protein comprises of polypeptide chains in the form of: (UHS MDCAT 2019)

  1. Cluster
  2. Spherical or curried up ball
  3. Long strands or fibrils
  4. Flat uncoiled chains
Show answer

Correct answer: (c) Long strands or fibrils

A fibrous protein is drawn out into long strands, which is what makes it strong and insoluble.

10.In glycine, R is __________. (UHS MDCAT 2019)

  1. Ethane
  2. Fatty acid
  3. H atom
  4. Competitive reversible
Show answer

Correct answer: (c) H atom

Glycine is the simplest amino acid; its side chain is a single hydrogen atom.

11.Most proteins are made up of: (UHS MDCAT 2019)

  1. 10 types of Amino acids
  2. 20 types of Amino acids
  3. 170 types Of Amino acids
  4. 16 types of Amino acids
Show answer

Correct answer: (b) 20 types of Amino acids

Twenty amino acids are coded for and make up almost all proteins.

12.Lipids contain double amount of energy as compared to the same amount of carbohydrates due to the presence of: (UHS MDCAT 2019)

  1. Higher proportion of C-H
  2. Higher proportion of C-O
  3. Higher proportion of Oxygen
  4. Low proportion of C-H bonds
Show answer

Correct answer: (a) Higher proportion of C-H

A fat is rich in carbon hydrogen bonds and poor in oxygen, so its oxidation yields more energy.

13.Sequence of amino acids, in a polypeptide chain of protein molecule, corresponds to the sequence of nucleotides on mRNA for that protein. If the reading frame of mRNA for a human protein is 993 nucleotides, including a stop codon at the end, how many amino acids would be incorporated in the polypeptide chain? (UHS MDCAT 2019)

  1. 93
  2. 330
  3. 331
  4. 993
Show answer

Correct answer: (b) 330

$993/3$ is $331$ codons, of which the last is a stop, so $330$ amino acids.

14.The process in which a complementary copy of the code from a gene is produced by RNA Polymerase in the nucleus: (UHS MDCAT 2019)

  1. Transcription
  2. Translation
  3. Proofreading
  4. DNA Replication
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Correct answer: (a) Transcription

Copying a gene into RNA is transcription.

15.Which one is an example of a Nucleotide? (UHS MDCAT 2019)

  1. Adenosine
  2. NAD
  3. ATP
  4. Guanine
Show answer

Correct answer: (c) ATP

A nucleotide is a base, a sugar and a phosphate; ATP is adenosine with three phosphates.

16.If sequence in DNA is CCCTAGAG, then what would be the sequence in messenger RNA after transcription ? (UHS MDCAT 2019)

  1. GGGAUCUC
  2. GGGATCTC
  3. GGAAUCUC
  4. GGGGTCTC
Show answer

Correct answer: (a) GGGAUCUC

RNA pairs G with C and A with U, so CCCTAGAG is transcribed as GGGAUCUC.

17.The nitrogen-containing bases in nucleotide are of two types; Purines and Pyrimidines. The purines bases are: (UHS MDCAT 2019)

  1. Adenine, Guanine, and Cytosine
  2. Guanine and Cytosine
  3. Adenine and Guanine
  4. Adenine and Thymine
Show answer

Correct answer: (c) Adenine and Guanine

Adenine and guanine have the double ring of a purine; cytosine and thymine are pyrimidines.

18.As a result of replication, parental DNA would become completely dispersed and that each strand of all the daughter molecules would be a mixture of old and new DNA. This is called as: (UHS MDCAT 2019)

  1. Dispersive idea
  2. Conservative idea
  3. Disruptive idea
  4. Semi-conservative idea
Show answer

Correct answer: (a) Dispersive idea

The dispersive idea would have each daughter molecule a patchwork of old and new; replication is in fact semi-conservative.

19.Meselson and Stahl transferred few bacteria grown in N15 medium to N14 medium for replicating their DNA. What would be the result after two rounds of replication? (UHS MDCAT 2019)

  1. 100% heavy duplex
  2. 100% hybrid duplex
  3. 50% hybrid duplex and 50% heavy duplex
  4. 50% hybrid duplex and 50% light duplex
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Correct answer: (d) 50% hybrid duplex and 50% light duplex

Each strand of the heavy duplex serves as a template, so after two rounds half is hybrid and half is fully light.

20.Ester linkages occur in: (UHS MDCAT 2019)

  1. Nucleic acids
  2. Nucleus
  3. Carbohydrates
  4. Proteins
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Correct answer: (a) Nucleic acids

The sugar and phosphate of the backbone are joined by phosphodiester, that is ester, linkages.

21.If 15 um size object is observed under light microscope, using 5X eyepiece and 10X objective, its magnified image size will be: (UHS MDCAT 2019)

  1. 750 um
  2. 50 um
  3. 500 um
  4. 250 um
Show answer

Correct answer: (a) 750 um

The magnification is $5\times10=50$, and $15\times50$ is $750\,\mu\mathrm{m}$.

22.Passive processes for the movement of molecules across cell surface membrane are: (UHS MDCAT 2019)

  1. osmosis and phagocytosis
  2. pinocytosis and facilitated diffusion
  3. facilitated diffusion and osmosis
  4. diffusion and exocytosis
Show answer

Correct answer: (c) facilitated diffusion and osmosis

Osmosis and facilitated diffusion both run down the gradient and cost no energy.

23.The structure present in a eukaryotic cell but absent in prokaryotic cells is; (UHS MDCAT 2019)

  1. DNA
  2. Ribosomes
  3. Cell surface membrane
  4. Nucleus
Show answer

Correct answer: (d) Nucleus

A prokaryote has DNA, ribosomes and a membrane, but no nucleus.

24.The prokaryotes possess ribosome with larger subunit of: (UHS MDCAT 2019)

  1. 70S
  2. 50S
  3. 60S
  4. 40S
Show answer

Correct answer: (b) 50S

The prokaryotic ribosome is 70S, made of a 50S and a 30S subunit.

25.Among the following, which cellular organelle contains circular DNA, similar to those found in bacteria? (UHS MDCAT 2019)

  1. Lysosome
  2. Nucleus
  3. Nucleosome
  4. Mitochondria
Show answer

Correct answer: (d) Mitochondria

Mitochondria carry a circular chromosome like a bacterium’s.

26.Site of mRNA translation (UHS MDCAT 2019)

  1. Lysosomes
  2. Ribosomes
  3. Cisternae
  4. Golgi body
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Correct answer: (b) Ribosomes

Translation happens on the ribosome.

27.Which cell organelle is responsible for protein modification? (UHS MDCAT 2019)

  1. Chloroplast
  2. Golgi body
  3. Ribosome
  4. Mitochondrion
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Correct answer: (b) Golgi body

The Golgi body trims, glycosylates and packages the proteins the reticulum sends it.

28.Smooth endoplasmic reticulum is responsible for the metabolism of: (UHS MDCAT 2019)

  1. Nucleic acids
  2. Proteins
  3. Carbohydrates
  4. Lipids
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Correct answer: (d) Lipids

The smooth endoplasmic reticulum makes and breaks down lipids and steroids.

29.The finger like infoldings, which are formed by inner membrane of mitochondria, are called: (UHS MDCAT 2019)

  1. Ribosomes
  2. Matrix
  3. Porin
  4. Cristae
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Correct answer: (d) Cristae

The infoldings of the inner mitochondrial membrane are the cristae.

30.Microtubule subunits (for spindle fibers) are synthesized in _______ phase. (UHS MDCAT 2019)

  1. G1
  2. M
  3. G2
  4. S
Show answer

Correct answer: (c) G2

The proteins for the spindle are made in G2, after replication and before division.

31.The phase of mitosis in which sister chromatids move towards opposite poles: (UHS MDCAT 2019)

  1. Anaphase
  2. Metaphase
  3. Prophase
  4. Telophase
Show answer

Correct answer: (a) Anaphase

The sister chromatids are pulled apart at anaphase.

32.During the G2 phase: (UHS MDCAT 2019)

  1. Chromosome number is duplicated
  2. The chromosomes are left with only one chromatid
  3. Energy is stored for Chromosome movement and mitotic specific proteins(Tubulin) are produced
  4. Specific enzymes are synthesized and DNA base units are accumulated
Show answer

Correct answer: (c) Energy is stored for Chromosome movement and mitotic specific proteins(Tubulin) are produced

G2 is the gap in which the proteins of the spindle are made and energy is laid in for division.

33.If stimulation is above ______, impulses travel to the brain along the sensory neuron. (UHS MDCAT 2019)

  1. Refractory period
  2. Resting potential
  3. Action potential
  4. Threshold potential
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Correct answer: (d) Threshold potential

A stimulus below the threshold sets off nothing; above it the impulse is full sized.

34.In an action potential, the permeability of sodium ions in the neurons increases due to; (UHS MDCAT 2019)

  1. Repolarization
  2. Sodium ions forming an ionic bonding
  3. The opening of sodium channels/gates
  4. The action of the acetylcholinesterase enzyme
Show answer

Correct answer: (c) The opening of sodium channels/gates

The sodium gates open and sodium rushes in down its gradient.

35.The reflex action is the phenomena which only involves: (UHS MDCAT 2019)

  1. receptors and effectors
  2. receptors, effectors, and spinal cord
  3. brain, receptors, and spinal cord
  4. receptors, neurons, and the brain
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Correct answer: (b) receptors, effectors, and spinal cord

A spinal reflex needs only the receptor, the cord and the effector; the brain learns of it afterwards.

36.Acetylcholine and Noradrenaline are two types of ______ used in our nervous system: (UHS MDCAT 2019)

  1. Enzymes
  2. Channel and carrier proteins in the cell membrane of a neuron.
  3. Neurotransmitters
  4. Hormones
Show answer

Correct answer: (c) Neurotransmitters

Both are neurotransmitters, acetylcholine in the parasympathetic and noradrenaline in the sympathetic system.

37.The main neurotransmitter for synapses is ______, which lie outside the central nervous system. (UHS MDCAT 2019)

  1. Acetylcholine
  2. Acetaldehyde
  3. Choline
  4. Phosphatidylcholine
Show answer

Correct answer: (a) Acetylcholine

Acetylcholine is the transmitter of the neuromuscular junction and the autonomic ganglia.

38.The type of energy, reduced by the enzymes, for biological reactions to occur is called the: (UHS MDCAT 2019)

  1. Light Energy
  2. Heat energy
  3. Active energy
  4. Activation energy
Show answer

Correct answer: (d) Activation energy

An enzyme lowers the activation energy of the reaction.

39.An example of competitive inhibition of an enzyme is the inhibition of; (UHS MDCAT 2019)

  1. Succinic dehydrogenase by malonic acid
  2. Cytochrome oxidase by cyanide
  3. Hexokinase by glucose
  4. Carbonic anhydrase by carbon dioxide
Show answer

Correct answer: (a) Succinic dehydrogenase by malonic acid

Malonic acid resembles succinic acid closely enough to occupy the active site of the dehydrogenase.

40.A student of chemical engineering mistakenly engulfed the toxic compound “A” which was a potent inhibitor of a certain enzyme. He was immediately brought to a hospital where the doctor injected, intravenously, substrate “B” to minimize the toxic effect of Compound A. His life was saved from serious damage. The treatment method shows that compound A was a ______ inhibitor. (UHS MDCAT 2019)

  1. Non competitive
  2. Irreversible
  3. Temperature sensitive
  4. Competitive reversible
Show answer

Correct answer: (d) Competitive reversible

Flooding the enzyme with substrate displaced the inhibitor, which is the mark of competitive reversible inhibition.

41.Change in frequency of alleles that occurs by chance Is called as: (UHS MDCAT 2019)

  1. Genetic drift
  2. Mutation
  3. Migration
  4. Natural selection
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Correct answer: (a) Genetic drift

Chance changes in allele frequency are genetic drift.

42.According to the theory of natural selection, organisms produce: (UHS MDCAT 2019)

  1. Offspring according to the resources available
  2. Offspring to create resources
  3. To create resources
  4. More offspring than supported
Show answer

Correct answer: (d) More offspring than supported

More young are born than can survive, and it is among these that selection works.

43.During spermatogenesis, the __________, which are haploid cells eventually mature into spermatozoa/mature sperms: (UHS MDCAT 2019)

  1. Spermatogonia
  2. Primary spermatocytes
  3. Spermatids
  4. Secondary spermatocytes
Show answer

Correct answer: (c) Spermatids

The spermatids are the haploid cells that grow tails and become spermatozoa.

44.Which hormonal pair would maintain the endometrium and make it receptive for implantation of embryo? (UHS MDCAT 2019)

  1. Luteinising Hormone and Progesterone
  2. Estrogen and Progesterone
  3. Estrogen and Follicle Stimulating Hormone
  4. Luteinising Hormone and Follicle Stimulating Hormone
Show answer

Correct answer: (b) Estrogen and Progesterone

Oestrogen builds the lining and progesterone holds it ready for the embryo.

45.Which of the following hormone stimulates the ovulation from the follicle into oviduct? (UHS MDCAT 2019)

  1. Estrogen
  2. Progesterone
  3. Luteinizing hormone
  4. Follicle stimulating hormone
Show answer

Correct answer: (c) Luteinizing hormone

The surge of luteinizing hormone bursts the follicle and releases the ovum.

46.Inside ovary, primary oocyte divides through first meiotic division, forming two haploid cells, the secondary oocyte and: (UHS MDCAT 2019)

  1. Ovum
  2. Oogonium
  3. Follicle cell
  4. Polar body
Show answer

Correct answer: (d) Polar body

The first meiotic division is unequal: one large secondary oocyte and one small polar body.

47.Thin filaments of muscles contain _____ chains of actin molecules. (UHS MDCAT 2019)

  1. Two
  2. One
  3. Three
  4. Four
Show answer

Correct answer: (a) Two

The thin filament is two chains of actin monomers twisted round each other.

48.The thick filaments, in a myofibril of muscles, are made of ________. (UHS MDCAT 2019)

  1. Myoglobin
  2. Myosin
  3. Actin
  4. Haemoglobin
Show answer

Correct answer: (b) Myosin

The thick filament is myosin.

49.The function of calcium ions in muscle contraction is to: (UHS MDCAT 2019)

  1. polarize visible light
  2. Aid in the transmission of nerve impulse
  3. Bind to troponin molecule and cause them to move
  4. Bind to tropomyosin molecule and cause them to form cross bridges
Show answer

Correct answer: (c) Bind to troponin molecule and cause them to move

Calcium binds troponin, which shifts the tropomyosin off the binding sites of actin.

50.Homozygous means: (UHS MDCAT 2019)

  1. alleles in an organism
  2. two different alleles of a gene.
  3. having two identical genes
  4. having two identical alleles of a gene.
Show answer

Correct answer: (d) having two identical alleles of a gene.

Homozygous means the two alleles of the gene are alike.

51.A person was married to his cousin and both are heterozygous for Sickle Cell anemia. Among their four kids, what will be proportion of homozygotes? (UHS MDCAT 2019)

  1. 75%
  2. 50%
  3. 100%
  4. 25%
Show answer

Correct answer: (b) 50%

The cross gives $1:2:1$, so half the children are homozygous, one way or the other.

52.Blood group AB is an example of __________ . (UHS MDCAT 2019)

  1. Complete dominance
  2. Recessive alleles
  3. Co-dominance
  4. Incomplete dominance
Show answer

Correct answer: (c) Co-dominance

Both alleles are expressed, so both antigens appear on the cells.

53.If a carrier haemophilic female (XHXh) is married to a haemophilic male (XhY). What will be the ratio of presence of haemophilia in the children. (UHS MDCAT 2019)

  1. 100% all females and males will be haemophilic
  2. Females have 50% chances of getting haemophilia and males will be 100% haemophilic
  3. Carrier female 25%, haemophilic female 25%, normal male 25% and 25% haemophilic male
  4. Females and males both have 50% chances of getting haemophilia
Show answer

Correct answer: (c) Carrier female 25%, haemophilic female 25%, normal male 25% and 25% haemophilic male

Half the daughters are carriers and half affected; half the sons are normal and half affected.

54.In which situation are genes, are not assorted independently, during meiosis in a chromosome? (UHS MDCAT 2019)

  1. When genes are linked and their loci are close to each other
  2. When some genes have mutated on the chromosome
  3. When there are too many Genes on a chromosome
  4. When genes are not linked and their loci are far apart
Show answer

Correct answer: (a) When genes are linked and their loci are close to each other

Genes close together on one chromosome are carried into the same gamete.

55.In genetics, the term locus refers to the ______ of the gene on the chromosome. (UHS MDCAT 2019)

  1. Position
  2. Frequency
  3. Copy
  4. Inversion
Show answer

Correct answer: (a) Position

The place a gene occupies on its chromosome is its locus.

56.Which of the following blood vessels contain semilunar valves? (UHS MDCAT 2019)

  1. Arteries
  2. Capillaries
  3. Veins
  4. Arterioles
Show answer

Correct answer: (c) Veins

Veins carry semilunar valves that stop the blood falling back.

57.The major function of basophils is to: (UHS MDCAT 2019)

  1. Destroy small particles by phagocytosis
  2. Release heparin to prevent blood clotting
  3. Transport oxygen
  4. Inactivate inflammation producing substances
Show answer

Correct answer: (b) Release heparin to prevent blood clotting

Basophils release heparin, which keeps the blood from clotting, and histamine.

58.Now-a-days every newborn gets regular shots of vaccine for polio. It contains _________ for polio to make a child immune against this disease. (UHS MDCAT 2019)

  1. Antibiotics
  2. Antibodies
  3. Antigens
  4. Antisera
Show answer

Correct answer: (c) Antigens

A vaccine carries the antigen, and the body makes its own antibodies against it.

59.A person got an infection, he became ill but then he survived. What do you think which of immunity he would have developed? (UHS MDCAT 2019)

  1. Active immunity
  2. Artificially induced active immunity
  3. Passive immunity
  4. Naturally induced active immunity
Show answer

Correct answer: (d) Naturally induced active immunity

He made his own antibodies in answer to a natural infection, so the immunity is naturally acquired and active.

60.A disease caused by gradual breakdown of the thin walls of alveoli is; (UHS MDCAT 2019)

  1. Tuberculosis
  2. Asthma
  3. Emphysema
  4. Bronchitis
Show answer

Correct answer: (c) Emphysema

Emphysema is the breakdown of the alveolar walls, which cuts the surface for gas exchange.

61.During inspiration, the space inside the chest cavity is increased due to: (UHS MDCAT 2019)

  1. The relaxation of the muscles of the diaphragm
  2. Relaxation of the external intercostal muscles
  3. Increased pressure
  4. The contraction of the muscles of the diaphragm
Show answer

Correct answer: (d) The contraction of the muscles of the diaphragm

The diaphragm contracts and flattens, which deepens the chest cavity.

62.Substances responsible for increasing the set point of the hypothalamus are called: (UHS MDCAT 2019)

  1. Androgens
  2. Pathogens
  3. Pepsin
  4. Prions
Show answer

Correct answer: (b) Pathogens

Pyrogens from the pathogens raise the setting of the hypothalamic thermostat, which is what a fever is.

63.The main nitrogenous excretory product of humans is: (UHS MDCAT 2019)

  1. Ammonia
  2. Urea
  3. Ammonium
  4. Uric acid
Show answer

Correct answer: (b) Urea

Humans convert their ammonia to urea in the liver.

64.The route of urine excretion from kidney to outside of body is: (UHS MDCAT 2019)

  1. Kidney -> ureter -> urinary bladder -> urethra
  2. Urinary bladder -> kidney -> ureter -> urethra
  3. Kidney -> urethra -> urinary bladder -> ureter
  4. Kidney -> ureter -> urethra -> urinary bladder
Show answer

Correct answer: (a) Kidney -> ureter -> urinary bladder -> urethra

Urine passes from the kidney down the ureter to the bladder and out through the urethra.

65.The Plasmid pBR322 has antibiotic resistance genes for: (UHS MDCAT 2019)

  1. Streptomycin
  2. Ampicillin and Tetracycline
  3. Tetracycline and mxycycline
  4. Ampicillin
Show answer

Correct answer: (b) Ampicillin and Tetracycline

pBR322 carries resistance to ampicillin and to tetracycline, which is how transformed cells are picked out.

66.Genetic engineering has been successfully used for producing; (UHS MDCAT 2019)

  1. Animals, with inferior traits.
  2. Transgenic mice for testing safety of polio vaccine before use in humans
  3. Animals, that have the same genetic constitution.
  4. None of the above
Show answer

Correct answer: (b) Transgenic mice for testing safety of polio vaccine before use in humans

Transgenic mice carrying the human receptor are used to test the safety of the polio vaccine.

67.Which enzyme is administered to the patients of Severe Combined Immunodeficiency Disease (SCID)? (UHS MDCAT 2019)

  1. Adenosine Deaminase (ADA)
  2. Pancreatic Enzyme
  3. ß galactosidase
  4. ß lactamase
Show answer

Correct answer: (a) Adenosine Deaminase (ADA)

Adenosine deaminase is the enzyme missing in ADA-SCID, and it is given by injection or by gene therapy.

68.Complementary DNA molecule is: (UHS MDCAT 2019)

  1. DNA from mRNA
  2. an artificial DNA
  3. single stranded DNA
  4. a small segment Of chromosomal DNA
Show answer

Correct answer: (a) DNA from mRNA

Complementary DNA is made from messenger RNA by reverse transcriptase, so it carries no introns.

69.DNA polymerase enzyme for PCR is isolated from bacteria, Thermus aquaticus, because; (UHS MDCAT 2019)

  1. It can work at high speed.
  2. It can withstand high denaturation temperature.
  3. It can withstand low denaturation temperature.
  4. It can be used again and again.
Show answer

Correct answer: (b) It can withstand high denaturation temperature.

Taq polymerase comes from a hot spring bacterium and survives the $95^{\circ}\mathrm{C}$ of each cycle.

Chemistry

70.Which two elements are isotopes? (UHS MDCAT 2019)

  1. 16X8 and 16Y8
  2. 14X8 and 15Y8
  3. 18X9 and 20Y10
  4. 12X6 and 12Y7
Show answer

Correct answer: (b) 14X8 and 15Y8

Isotopes have the same proton number and different mass numbers.

71.Solution contains 85.5 g of sucrose (C12H22O11) in 250 cm3. What is its molarity? (UHS MDCAT 2019)

  1. 1 M
  2. 0.5 M
  3. 0.25 M
  4. 2 M
Show answer

Correct answer: (a) 1 M

$85.5/342$ is $0.25$ mole in $0.25\,\mathrm{dm^3}$, that is $1\,\mathrm{M}$.

72.The average atomic mass of Boron is 10.8. It has two isotopes of masses 10 and 11 respectively. What is the percentage of isotope with the average mass of 10? (UHS MDCAT 2019)

  1. 20%
  2. 60%
  3. 80%
  4. 50%
Show answer

Correct answer: (a) 20%

$10x+11(1-x)=10.8$ gives $x=0.2$, that is $20\%$.

73.The number of moles of water in 1 kg ice are: (UHS MDCAT 2019)

  1. 50 moles
  2. 100 moles
  3. 1000 moles
  4. 55.5 moles
Show answer

Correct answer: (d) 55.5 moles

$1000/18$ is about $55.5$ moles.

74.How many moles of Calcium Carbonate are present in 1.75 kg of Calcium Carbonate (Ar of Ca = 40, Ar of C = 12, Ar of O = 16) (UHS MDCAT 2019)

  1. 1.75 mol
  2. 1750 mol
  3. 0.0175 mol
  4. 17.5 mol
Show answer

Correct answer: (d) 17.5 mol

$1750/100$ is $17.5$ moles.

75.During stoichiometric calculations, which of the following laws must be followed? (UHS MDCAT 2019)

  1. Dalton's law
  2. Avogadro's law
  3. Law of conservation of mass
  4. Law of conservation of energy
Show answer

Correct answer: (c) Law of conservation of mass

Matter is neither made nor destroyed, so the equation must balance.

76.Which of the following is the electronic configuration of Cr? (UHS MDCAT 2019)

  1. [Ar] 3d5 4s2
  2. [Ar] 3d5 4s1
  3. [Ar] 3d4 4s2
  4. [Ar] 3d6 4s0
Show answer

Correct answer: (b) [Ar] 3d5 4s1

A half filled d subshell is stable, so chromium is $[\mathrm{Ar}]3d^5 4s^1$.

77.All the collisions between the particles of gases are elastic in nature. What is meant by “Elastic Collisions”? (UHS MDCAT 2019)

  1. No change in the total kinetic energy
  2. The velocity of the molecules changes
  3. No change in potential energy during the collisions
  4. No change in mass during the collisions
Show answer

Correct answer: (a) No change in the total kinetic energy

An elastic collision is one in which the total kinetic energy is unchanged.

78.Which of the following substances exhibits hydrogen bonding? (UHS MDCAT 2019)

  1. H2S
  2. SiH4
  3. NH3
  4. HI
Show answer

Correct answer: (c) NH3

Only ammonia has hydrogen bound to nitrogen, oxygen or fluorine.

79.The pH of 10-2 M aqueous solution of sodium hydroxide is: (UHS MDCAT 2019)

  1. 14
  2. 10
  3. 12
  4. 13
Show answer

Correct answer: (c) 12

$10^{-2}\,\mathrm{M}$ alkali gives pOH $2$, so the pH is $12$.

80.The Ka values of HCI, CH3COOH, HF, and H2SO4 are 107, 1.85 x 10-5, 6.7 x 10-5 and 102 respectively. The decreasing order of acidic strength is: (UHS MDCAT 2019)

  1. CH3COOH > HF > H2SO4 > HCI
  2. HCI > H2SO4 > HF > CH3COOH
  3. HCl > CH3COOH > HF > H2SO4
  4. HCl > HF > H2SO4 > CH3COOH
Show answer

Correct answer: (b) HCI > H2SO4 > HF > CH3COOH

The larger the acid dissociation constant the stronger the acid.

81.In contact process, to which substance adequate quantities of water is added to convert it to sulphuric acid? (UHS MDCAT 2019)

  1. H2S2O7
  2. HSO4-
  3. SO3
  4. S
Show answer

Correct answer: (a) H2S2O7

Sulphur trioxide is absorbed in sulphuric acid to give oleum, and water is then added to that.

82.What is the measure of activation energy in an endothermic reaction? (UHS MDCAT 2019)

  1. The energy of activation of backward reaction is less than that of forward reaction
  2. The energy of activation of backward reaction is more that that of forward reaction.
  3. The energy of activation of forward reaction is less than that of backward reaction.
  4. The energy of activation of forward – backward reaction is same.
Show answer

Correct answer: (a) The energy of activation of backward reaction is less than that of forward reaction

The products lie above the reactants, so the barrier is lower seen from the product side.

83.If the energy of activation of a chemical reaction is very low, the rate of that chemical reaction is observed to be very high because? (UHS MDCAT 2019)

  1. Concentration of the reactants becomes irrelevant
  2. Reaction proceeds without any transition state
  3. Number of efficient or fruitful collisions increase
  4. Molecules of the reactants move slowly
Show answer

Correct answer: (c) Number of efficient or fruitful collisions increase

A low barrier means a large fraction of collisions carry enough energy to succeed.

84.Which of the equations shows ‘’twice’’ the enthalpy change of neutralization as the following equation (UHS MDCAT 2019)

  1. MgCO3 + 2HCl -> MgCl2 + CO2 + H2O
  2. KOH + HCl -> KCl + H2P
  3. NH4Cl + NaOH -> NaCl + H2O + NH3
  4. H2SO4 + Mg(OH)2 -> MgSO4 + 2H2O
Show answer

Correct answer: (d) H2SO4 + Mg(OH)2 -> MgSO4 + 2H2O

A diprotic acid with a dibasic alkali makes two moles of water, so twice the heat is given out.

85.Oxidation number of particular element can be directly or indirectly inferred from its: (UHS MDCAT 2019)

  1. Group number
  2. Atomic size
  3. Atomic mass
  4. Physical state
Show answer

Correct answer: (a) Group number

The group number gives the number of outer electrons, and so the usual oxidation state.

86.Which one of the following molecules has sp3 hybridization? (UHS MDCAT 2019)

  1. CH4
  2. C2H4
  3. CO2
  4. C2H2
Show answer

Correct answer: (a) CH4

Carbon in methane has four sigma bonds and no lone pair.

87.Which of the following set constitutes of all the molecules and ions of non-planar geometry? (UHS MDCAT 2019)

  1. PH4+, NH3, SO3, Benzene
  2. CH4, NH4 +, MnO4- , NF3
  3. Ethene, H2O, BeCl2, H2S
  4. SO2, C2H4, BF3, NO3-
Show answer

Correct answer: (b) CH4, NH4 +, MnO4- , NF3

Methane, the ammonium ion, the permanganate ion and nitrogen trifluoride are all three dimensional.

88.In the second period of elements, although oxygen lies next to nitrogen yet its ionization first energy is lower than that of nitrogen because? (UHS MDCAT 2019)

  1. Oxygen is paramagnetic in character
  2. Nuclear charger of oxygen is greater than nitrogen
  3. Oxygen has higher electron affinity
  4. In oxygen, there exists repulsion between pair of electrons present in the same orbital of valence shell.
Show answer

Correct answer: (d) In oxygen, there exists repulsion between pair of electrons present in the same orbital of valence shell.

Nitrogen has a half filled p subshell; in oxygen one orbital holds a pair, and their repulsion makes that electron easier to remove.

89.Ionization energy decreases down the group, from top to bottom, due to: (UHS MDCAT 2019)

  1. Increase in atomic mass
  2. Increase in shielding effect of the intervening electrons
  3. Increase in proton number
  4. Decrease in atomic size
Show answer

Correct answer: (b) Increase in shielding effect of the intervening electrons

More inner shells screen the outer electron better, so it is easier to remove.

90.Modern periodic table is arranged in ascending order of? (UHS MDCAT 2019)

  1. Nucleon number
  2. Atomic mass
  3. Proton number
  4. Mass number
Show answer

Correct answer: (c) Proton number

The modern table is arranged by atomic, that is proton, number.

91.Which of the following element is not present in halogens? (UHS MDCAT 2019)

  1. I
  2. Cl
  3. Fe
  4. F
Show answer

Correct answer: (c) Fe

Iron is a transition metal; the halogens are group VII.

92.Copper is a typical transition metal. Its atomic number is 29. In which oxidation state does it have a partially filled orbital in d-subshell? (UHS MDCAT 2019)

  1. Cu
  2. Cu+
  3. Cu-
  4. Cu2+
Show answer

Correct answer: (d) Cu2+

Copper(I) is $3d^{10}$ and full; copper(II) is $3d^9$, which is partly filled.

93.Which of the following molecule shows cis- trans isomers? (UHS MDCAT 2019)

  1. C2H4
  2. C2H2Cl4
  3. C2H2Br2
  4. C2HCl3
Show answer

Correct answer: (c) C2H2Br2

1,2-dibromoethene has one substituent on each carbon of the double bond, so cis and trans differ.

94.Alkenes undergo: (UHS MDCAT 2019)

  1. Electrophilic Addition
  2. Electrophilic substitution
  3. Nucleophilic substitution
  4. Nucleophilic addition
Show answer

Correct answer: (a) Electrophilic Addition

The pi electrons of the double bond attract an electrophile, which then adds across it.

95.Which derivative of benzene shows maximum reactivity in electrophilic substitution reactions? (UHS MDCAT 2019)

  1. Benzoic acid
  2. Methyl benzene
  3. Benzaldehyde
  4. Nitrobenzene
Show answer

Correct answer: (b) Methyl benzene

The methyl group feeds electrons into the ring; the other three groups pull them out.

96.Which product is obtained by the hydrolysis of 1-chlorobutane with the aqueous sodium hydroxide? (UHS MDCAT 2019)

  1. 1-butanal
  2. 1-butanol
  3. 1-butene
  4. Butanone
Show answer

Correct answer: (b) 1-butanol

Aqueous alkali substitutes hydroxide for the halogen and gives the alcohol.

97.Which of the following reactions is used for the production of alcohols on industrial scale? (UHS MDCAT 2019)

  1. Hydrogenation of alkenes
  2. Hydration of alkenes
  3. Hydrohalogenation of alkenes
  4. Hydroxylation of alkenes
Show answer

Correct answer: (b) Hydration of alkenes

Ethene and steam over phosphoric acid give ethanol, which is how most industrial alcohol is made.

98.Treatment of ethene with cold sulphuric acid, followed by reaction with boiling water, yields: (UHS MDCAT 2019)

  1. Ethane
  2. Ethanal
  3. Ethanol
  4. Ethyne
Show answer

Correct answer: (c) Ethanol

The ethyl hydrogen sulphate formed in the cold hydrolyses on boiling to ethanol.

99.Identification tests for functional groups of organic compounds are associated with specific observations. Tollen’s reagent is an ammoniacal silver nitrate solution, which is used for the identification of a functional group X with an observation O. Identify X and O. (UHS MDCAT 2019)

  1. X = Aldehyde O = Silver mirror
  2. X = Ketone, O = grey precipitate
  3. X = Ketone, O = Silver mirror
  4. X = Aldehyde O = Red precipitate
Show answer

Correct answer: (a) X = Aldehyde O = Silver mirror

Only an aldehyde reduces Tollens’ reagent, leaving a mirror of silver.

100.Ketones can be made by oxidation of: (UHS MDCAT 2019)

  1. Aldehydes
  2. Primary Alcohols
  3. Secondary Alcohols
  4. Tertiary Alcohols
Show answer

Correct answer: (c) Secondary Alcohols

A secondary alcohol has one hydrogen on the carbinol carbon, so oxidation stops at the ketone.

101.Which type of reaction takes place when a carbonyl compound is treated with a mixture of NaCN and an acid? (UHS MDCAT 2019)

  1. Electrophilic addition reaction
  2. Substitution reaction
  3. Nucleophilic addition reaction
  4. Displacement reaction
Show answer

Correct answer: (c) Nucleophilic addition reaction

The cyanide ion attacks the electron poor carbonyl carbon, so the step is nucleophilic addition.

102.Which of the following will give a positive test with Tollen’s reagent? (UHS MDCAT 2019)

  1. Tertiary alcohols
  2. Carboxylic acids
  3. Aldehydes
  4. Ketones
Show answer

Correct answer: (c) Aldehydes

Only an aldehyde reduces Tollens’ reagent.

103.Which of the following compounds will give a secondary alcohol after reaction with NaBH4? (UHS MDCAT 2019)

  1. CH3COCH3
  2. CH3COOCH3
  3. CH3CH2CHO
  4. CH3CH2COOH
Show answer

Correct answer: (a) CH3COCH3

Sodium borohydride reduces a ketone to a secondary alcohol.

104.Nitriles (RCN), on hydrolysis, in the presence of a mineral acid yield: (UHS MDCAT 2019)

  1. Ethers
  2. Carboxylic acids
  3. Aldehydes
  4. Alcohols
Show answer

Correct answer: (b) Carboxylic acids

A nitrile hydrolyses to the carboxylic acid and ammonia.

105.Carboxylic acids can be reduced to corresponding alcohols. Which of the following reagent can be used for this purpose? (UHS MDCAT 2019)

  1. KMnO4
  2. LiAlH4
  3. K2Cr2O4
  4. H2SO4
Show answer

Correct answer: (b) LiAlH4

Lithium aluminium hydride reduces the carboxyl group all the way to a primary alcohol.

106.Which of the following reagent is required for preparation of acyl chloride (CH3COCl) from ethanoic aicd? (UHS MDCAT 2019)

  1. PCl5
  2. POCl3
  3. CH3Cl
  4. HCl
Show answer

Correct answer: (a) PCl5

Phosphorus pentachloride replaces the hydroxyl group of the acid with chlorine.

107.Which balanced chemical equation show the formation of ethanoyl chloride using thionyl chloride? (UHS MDCAT 2019)

  1. HCOOH + SOCl2 —> HCOCI + SO2 + HCI
  2. CH3CH2COOH + 2SOCl -> CH3CH2COCl + SO2 + HCI
  3. CH3CH2COOH + 2SOCl -> CH3CH2COC1 + SO3 + HCI
  4. CH3COOH + SOCl2 -> CH3COCl + SO2 + HCI
Show answer

Correct answer: (d) CH3COOH + SOCl2 -> CH3COCl + SO2 + HCI

Ethanoic acid with thionyl chloride gives ethanoyl chloride, sulphur dioxide and hydrogen chloride.

108.Amino acids are bi-functional compounds, with a general formula NH2CH(R)CO2H. A tripeptide is formed between Alanine (ala), Glycine (gly), and lysine (lys). There is no repetition of amino acid in this tri-peptide; Suggest how many tri-peptides are possible? (UHS MDCAT 2019)

  1. 9
  2. 6
  3. 3
  4. 12
Show answer

Correct answer: (b) 6

Three different residues can be arranged in $3!$ orders, that is six.

109.Which of the following bond is responsible for joining the amino acids in proteins? (UHS MDCAT 2019)

  1. Peptide Bond
  2. Ionic Bond
  3. Metallic Bond
  4. Disulfide Bond
Show answer

Correct answer: (a) Peptide Bond

Amino acids are joined by peptide bonds.

110.According to Watson and Crick’s model of DNA, the DNA molecule consists of a double helix. What type of forces are responsible to keep two strands of DNA together? (UHS MDCAT 2019)

  1. Van der Waals forces
  2. Ionic bonding
  3. Hydrogen bonding
  4. Dipole-induced dipole forces
Show answer

Correct answer: (c) Hydrogen bonding

The bases of the two strands are paired by hydrogen bonds.

111.An intermolecular force of attraction X is relatively stronger than the other intermolecular forces. It stabilizes alpha-helix and Beta-pleated sheets of proteins. The double helical structure of DNA is also stabilized by this force of attraction. Identify X. (UHS MDCAT 2019)

  1. Van Der Waals Forces
  2. Hydrogen bonding
  3. Ionic interactions
  4. Dipole dipole attraction
Show answer

Correct answer: (b) Hydrogen bonding

Hydrogen bonds hold the alpha helix, the pleated sheet and the two strands of DNA alike.

112.Disposable cups are made of a polymer ‘polystyrene’. Polystyrene is: (UHS MDCAT 2019)

  1. A polyamide
  2. A condensation polymer
  3. An addition polymer
  4. A polyester
Show answer

Correct answer: (c) An addition polymer

Polystyrene is made by adding styrene monomers with nothing eliminated.

113.Which one of the following compounds is an additional polymer? (UHS MDCAT 2019)

  1. Polyvinyl chloride
  2. Nylon
  3. Carbohydrate
  4. Polyester
Show answer

Correct answer: (a) Polyvinyl chloride

Poly(vinyl chloride) is built by adding monomers with nothing eliminated.

Physics

114.For projectile motion, in the absence of air resistance: (UHS MDCAT 2019)

  1. Horizontal acceleration is zero
  2. Vertical acceleration is zero
  3. Horizontal force is constant
  4. Vertical speed is constant
Show answer

Correct answer: (a) Horizontal acceleration is zero

Gravity acts only downwards, so nothing accelerates the projectile horizontally.

115.The range Of the projectile depends upon the velocity of the projection and the angle of the projection i.e 45. For a fixed velocity, when the angle of projection is larger than 45. Which of the following is correct? (UHS MDCAT 2019)

  1. The height attained by the projectile will be more but the range is less
  2. Both the height and the range attained by the projectile will be more.
  3. The height attained by the projectile will be less but the range is more.
  4. Both the height and the range attained by the projectile will be less.
Show answer

Correct answer: (a) The height attained by the projectile will be more but the range is less

Above $45^{\circ}$ more of the velocity goes into the vertical, so the projectile rises higher but lands nearer.

116.If two objects of equal masses ‘m’ are moving towards each other with the same speeds ‘v’ then what will be the total final momentum after elastic head-on collision? (UHS MDCAT 2019)

  1. mv kg m/s
  2. – mv kg's
  3. 2 mv kg's
  4. 0 kg m/s
Show answer

Correct answer: (d) 0 kg m/s

The two momenta are equal and opposite, so their sum is zero before and after.

117.Work done, due to centripetal force, for circular motion will be: (UHS MDCAT 2019)

  1. Reduced
  2. Zero
  3. Maximum
  4. Half
Show answer

Correct answer: (b) Zero

The centripetal force is always at right angles to the motion, so it does no work.

118.Which of the following statement shows that no work is done? (UHS MDCAT 2019)

  1. Pushing a car to start it moving
  2. Lifting the weights.
  3. The moon Orbiting the earth.
  4. Writing an essay on a page.
Show answer

Correct answer: (c) The moon Orbiting the earth.

The moon moves at right angles to the pull on it, so gravity does no work.

119.An automobile is moving forwards with uniform velocity due to the force exerted by its engine. If the force is doubled with the velocity remaining constant what happens to its total power? (UHS MDCAT 2019)

  1. It is squared
  2. It is halved
  3. It is doubled
  4. It does not change
Show answer

Correct answer: (c) It is doubled

$P=Fv$, so at the same speed twice the force is twice the power.

120.An object is moving along a circular path of radius 4m. What will be its angular displacement if it moves 14 m on this circular path? (UHS MDCAT 2019)

  1. 5.0 radians
  2. 3.5 radians
  3. 4.5 radians
  4. 5.5 radians
Show answer

Correct answer: (b) 3.5 radians

$\theta=s/r=14/4$, that is $3.5$ radians.

121.When the length of simple pendulum is doubled, the ratio of its new time period to old time period is: (UHS MDCAT 2019)

  1. 3√2
  2. 1√2
  3. 2√2
  4. √2
Show answer

Correct answer: (d) √2

$T=2\pi\sqrt{l/g}$ goes as the square root of the length.

122.In simple harmonic motion, acceleration will be maximum, when object is at: (UHS MDCAT 2019)

  1. Maximum displacement from the mean position
  2. Center position
  3. Half of the maximum displacement from mean position
  4. Mean position
Show answer

Correct answer: (a) Maximum displacement from the mean position

$a=-\omega^2x$, so the acceleration is greatest where the displacement is greatest.

123.The sum of all forms of molecular energies (Kinetic and Potential) of a substance is termed as? (UHS MDCAT 2019)

  1. Elastic energy
  2. Absolute energy
  3. Internal energy
  4. Heat energy
Show answer

Correct answer: (c) Internal energy

The sum of the kinetic and potential energies of all the molecules is the internal energy.

124.Molecules Of a gas at constant pressure for a fixed amount of gas have average kinetic energy X. Increasing temperature from 27 C to 327C, average K.E. of molecules will become: (UHS MDCAT 2019)

  1. 20X
  2. 300X
  3. 200X
  4. 2X
Show answer

Correct answer: (d) 2X

Mean kinetic energy goes as the absolute temperature, and $600/300$ is two.

125.Electric field strength at a point between oppositely charged plates is ‘E’. If the distance between plates is reduced to half, what will be the new value of electric intensity? (UHS MDCAT 2019)

  1. 4E
  2. E/2
  3. E/4
  4. 2E
Show answer

Correct answer: (d) 2E

$E=V/d$ between parallel plates, so halving the separation doubles the field.

126.A particle, carrying a charge of 5e, falls through a potential difference of 25 V. What would be energy acquired by the particle in ‘J’. (UHS MDCAT 2019)

  1. 1.6 x 10-19J
  2. 125 J
  3. 125 x 10-19 J
  4. 125 x 1.6 x 10-19 J
Show answer

Correct answer: (d) 125 x 1.6 x 10-19 J

$W=qV=5e\times25$, that is $125\times1.6\times10^{-19}\,\mathrm{J}$.

127.Electric field strength of a point charge is E and electric potential is V, at a distance ‘r’ from the point charge. What is the electric potential at a point for the same point charge where electric field strength is E/4? (UHS MDCAT 2019)

  1. 4V
  2. 2V
  3. V/2
  4. V/4
Show answer

Correct answer: (c) V/2

$E$ goes as $1/r^2$ and $V$ as $1/r$, so a quarter of the field means twice the distance and half the potential.

128.Kirchhoff’s first law/rule corresponds to: (UHS MDCAT 2019)

  1. Law of conservation of energy
  2. Law Of conservation Of momentum
  3. Law of conservation of charge
  4. Law of conservation of mass
Show answer

Correct answer: (c) Law of conservation of charge

What flows into a junction must flow out of it, which is the conservation of charge.

129.Calculate the rate at which energy is transferred by 220 V mains supply, which provides a current of 0.1 A to a LED? (UHS MDCAT 2019)

  1. 2.2 W
  2. 2.2 kW
  3. 22 kW
  4. 22 W
Show answer

Correct answer: (d) 22 W

$P=VI=220\times0.1$, that is $22\,\mathrm{W}$.

130.A copper wire has length L and cross-sectional area A. Its resistance is R. If we halved the length and halved the diameter of wire, then what will be the resistance of this wire? (UHS MDCAT 2019)

  1. 4R
  2. 3R
  3. 2R
  4. R
Show answer

Correct answer: (c) 2R

Halving the diameter quarters the area, so $R=\rho(L/2)/(A/4)$ is $2R$.

131.If a conductor of length 7m is placed in a magnetic field of strength 0.3 T carrying current 1 A, parallel to the field. What will be the force, acting on it, due to this magnetic field? (UHS MDCAT 2019)

  1. 7 N
  2. 0 N
  3. 3.1 N
  4. 2.1 N
Show answer

Correct answer: (b) 0 N

$F=BIL\sin\theta$, and with the current along the field the sine is zero.

132.The horizontal component of Earth magnetic flux density is 1.8 x 10-6 T. The current in a horizontal cable is 160 A. Calculate the maximum force per unit length? (UHS MDCAT 2019)

  1. 2.88x 10-6N/m
  2. 2.88x 10-4N/m
  3. 2.88x 10-2N/m
  4. 2.88x 10-8N/m
Show answer

Correct answer: (b) 2.88x 10-4N/m

$F/L=BI=1.8\times10^{-6}\times160$, that is $2.88\times10^{-4}\,\mathrm{N\,m^{-1}}$.

133.If we change the magnetic flux linking a coil by rotating the coil in a constant magnetic field, the rate of change of this flux is: (UHS MDCAT 2019)

  1. Proportional to the emf produced in it
  2. Proportional to the material Of the coil
  3. Proportional to the resistance of the coil
  4. Proportional to the change in magnetic field
Show answer

Correct answer: (a) Proportional to the emf produced in it

Faraday’s law makes the emf equal to the rate of change of flux.

134.If we give a direct current to the transformer’s primary coil, then there will be: (UHS MDCAT 2019)

  1. No emf produced in the secondary
  2. More emf in the secondary
  3. Equal emf produced in the secondary
  4. Less emf produced in the secondary
Show answer

Correct answer: (a) No emf produced in the secondary

A steady current gives a steady flux, and only a changing flux induces an emf.

135.The wavelength of the electromagnetic wave having frequency of 3 kHz will be? (UHS MDCAT 2019)

  1. 120 km
  2. 100 km
  3. 80 km
  4. 140 km
Show answer

Correct answer: (b) 100 km

$\lambda=c/f=3\times10^8/3\times10^3$, that is $10^5\,\mathrm{m}$, or $100\,\mathrm{km}$.

136.The direction of current through the load resistance of a full-wave rectification circuit: (UHS MDCAT 2019)

  1. remains constant
  2. inverts for positive cycle
  3. changes for every cycle
  4. inverts for negative cycle
Show answer

Correct answer: (a) remains constant

Both half cycles are turned the same way up, so the current through the load never reverses.

137.The value and units of the Planck constant ‘h’ can be expressed as: (UHS MDCAT 2019)

  1. 3.63 x 10-34 Js
  2. 6.63 x 10-34 Js-1
  3. 6.63 x 10-34 Js
  4. 6.63 x 10-43 Js
Show answer

Correct answer: (c) 6.63 x 10-34 Js

Planck’s constant is $6.63\times10^{-34}\,\mathrm{J\,s}$.

138.Minimum energy required to eject an electron from metal surface is called: (UHS MDCAT 2019)

  1. Stopping potential
  2. Electromotive force
  3. Work function
  4. Threshold frequency
Show answer

Correct answer: (c) Work function

That least energy is the work function of the metal.

139.Calculate the energy of a photon, with a frequency of 3.0 x 1018 Hz. (UHS MDCAT 2019)

  1. 19.89 x 10-16 J
  2. 11.89 x 10-16 J
  3. 1.89 x 10-16 J
  4. 19.89 x 10-18 J
Show answer

Correct answer: (a) 19.89 x 10-16 J

$E=hf=6.63\times10^{-34}\times3.0\times10^{18}$, that is $19.89\times10^{-16}\,\mathrm{J}$.

140.Heavy nucleus of atoms go through fission so that they can: (UHS MDCAT 2019)

  1. absorb low amount of energy
  2. absorb high amount of energy
  3. reduce their binding energy nucleon
  4. increase their binding energy per nucleon
Show answer

Correct answer: (d) increase their binding energy per nucleon

The fragments lie nearer the peak of the binding energy curve, and the difference is released.

141.What is the quark composition of a Proton? (UHS MDCAT 2019)

  1. Two up quarks and one down quark
  2. Two up quarks and one strange quark
  3. One up quark and two strange quarks
  4. Two down quarks and one up quark
Show answer

Correct answer: (a) Two up quarks and one down quark

A proton is two up quarks and one down quark.

142.In relation, which quantity is represented by λ? (UHS MDCAT 2019)

  1. Decay constant
  2. Half life
  3. Activity
  4. Wavelength
Show answer

Correct answer: (a) Decay constant

$\lambda$ is the decay constant, the probability of decay per second.

English

143.The accident happened due to the driver’s _____ . (UHS MDCAT 2019)

  1. Negligence
  2. Reluctance
  3. Regret
  4. Quotation
Show answer

Correct answer: (a) Negligence

Negligence is a failure to take proper care, which is what causes an accident.

144.They sometimes feel a _____ for the mountains and the sea. (UHS MDCAT 2019)

  1. Yearning
  2. Yapping
  3. Yelling
  4. Yielding
Show answer

Correct answer: (a) Yearning

A yearning is a strong longing for something.

145.I ______ caution in interpreting these results. (UHS MDCAT 2019)

  1. Urge
  2. Usher
  3. Usurp
  4. Uproot
Show answer

Correct answer: (a) Urge

To urge caution is to press it strongly on someone.

146.The parents were stunned when they saw that children had created complete _____ in the bedroom. (UHS MDCAT 2019)

  1. Knack
  2. Groggy
  3. Dank
  4. Mayhem
Show answer

Correct answer: (d) Mayhem

Mayhem is violent disorder.

147.She was feeling ______ even after five hours of the surgery. (UHS MDCAT 2019)

  1. Mumbled
  2. Haggard
  3. Pally
  4. Grope
Show answer

Correct answer: (b) Haggard

Haggard means drawn and exhausted in appearance.

148.The new teacher showed no _____ about hitting the students. (UHS MDCAT 2019)

  1. Quakes
  2. Qualms
  3. Quarrel
  4. Quotation
Show answer

Correct answer: (b) Qualms

A qualm is a misgiving about doing something.

149.The culpable child _____ some words to her mother for pardoning his delinquency. (UHS MDCAT 2019)

  1. Mumbled
  2. Showy
  3. Rude
  4. Crazy
Show answer

Correct answer: (a) Mumbled

To mumble is to speak indistinctly, as a guilty child might.

150.The prince abdicated the crown and returned to his castle. Abdicated means; (UHS MDCAT 2019)

  1. Gave up
  2. Sold
  3. Reinvested into
  4. Auctioned
Show answer

Correct answer: (a) Gave up

To abdicate is to give up a throne or an office.

151.In the following question, four alternative sentences are given. Choose the CORRECT option. (UHS MDCAT 2019)

  1. It is healthful to eat a variety of food.
  2. It Were healthful to eat a variety of food.
  3. It is healthful to ate a variety of food.
  4. It were healthful to ate a variety of food.
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Correct answer: (a) It is healthful to eat a variety of food.

It is takes the singular present, and the infinitive after healthful is to eat.

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