MDCAT 2017

MDCAT 2017 Past Paper with Answers (All Subjects)

184 MCQs from MDCAT 2017 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 2017 by subject

Biology

1.Size of virus ranges in: (UHS MDCAT 2017)

  1. 20 to 250 nm
  2. 25 to 250 nm
  3. 25 to 300 nm
  4. 20 to 300 nm
Show answer

Correct answer: (a) 20 to 250 nm

Viruses run from about $20$ to $250\,\mathrm{nm}$ across.

2.Reverse transcriptase is the function of: (UHS MDCAT 2017)

  1. Pox virus
  2. HIV
  3. Paramyxovirus
  4. Tobacco mosaic virus
Show answer

Correct answer: (b) HIV

HIV is a retrovirus and carries reverse transcriptase in its core.

3.In Citric Acid Cycle Acetyl CoA combines with: (UHS MDCAT 2017)

  1. Glucose
  2. CO2
  3. Rubisco
  4. Oxaloacetate
Show answer

Correct answer: (d) Oxaloacetate

Acetyl coenzyme A joins oxaloacetate to give citrate and start the cycle.

4.The term glycolysis refers to the conversion of: (UHS MDCAT 2017)

  1. Pyruvate to Glucose
  2. Glucose to Pyruvate
  3. Citric acid to CO2
  4. Both Pyruvate to Glucose and Glucose to Pyruvate
Show answer

Correct answer: (b) Glucose to Pyruvate

Glycolysis is the splitting of glucose to two molecules of pyruvate.

5.The type of carbohydrate which has high molecular weight and is sparingly soluble in water is: (UHS MDCAT 2017)

  1. Monosaccharides
  2. Disaccharides
  3. Polysaccharides
  4. Maltose
Show answer

Correct answer: (c) Polysaccharides

A polysaccharide is a long chain, so it is heavy and barely soluble.

6.Give the general formula of monosaccharides and polysaccharides. (UHS MDCAT 2017)

  1. (CH2O)n and Cn(H2O)2n
  2. (CH2O)2n and Cn(H2O)n
  3. (CH2O)n and Cn(H2O)n-1
  4. (CH2O)n-1 and Cn(H2O)n+1
Show answer

Correct answer: (c) (CH2O)n and Cn(H2O)n-1

A monosaccharide is $(\mathrm{CH_2O})_n$; a polysaccharide loses a water at each link.

7.How many essential amino acids are there? (UHS MDCAT 2017)

  1. Three
  2. Six
  3. Nine
  4. Twelve
Show answer

Correct answer: (c) Nine

Nine of the twenty amino acids cannot be made by the body and must come in the diet.

8.The type of bonding in ?-Helix; (UHS MDCAT 2017)

  1. 1,2 Glycosidic Linkage
  2. Ionic Bond
  3. Disulfide Bond
  4. Hydrogen Bond
Show answer

Correct answer: (d) Hydrogen Bond

Hydrogen bonds between the peptide groups hold the coil of the alpha helix.

9.The sequence of amino acids is major factor in which type of protein classification; (UHS MDCAT 2017)

  1. Primary Proteins
  2. Secondary Proteins
  3. Tertiary Proteins
  4. Both Primary and Tertiary Proteins
Show answer

Correct answer: (a) Primary Proteins

The order of the amino acids is the primary structure.

10.Among the following, which acid is an unsaturated acid: (UHS MDCAT 2017)

  1. Butyric Acid
  2. Oleic Acid
  3. Palmitic Acid
  4. Both Oleic Acid and Palmitic Acid
Show answer

Correct answer: (b) Oleic Acid

Oleic acid has a double bond in its chain; butyric and palmitic acids are saturated.

11.The process in which an RNA copy of the DNA sequence encoding the gene is produced (UHS MDCAT 2017)

  1. Translation
  2. Transcription
  3. Polymerization
  4. Genesis
Show answer

Correct answer: (b) Transcription

Copying a gene into RNA is transcription.

12.In translation, the termination codon is: (UHS MDCAT 2017)

  1. UAA
  2. UCG
  3. AUG
  4. UUU
Show answer

Correct answer: (a) UAA

UAA, UAG and UGA are the stop codons.

13.What is the subunit of DNA (UHS MDCAT 2017)

  1. Phosphoric Acid
  2. Base
  3. Nucleotide
  4. Sugar
Show answer

Correct answer: (c) Nucleotide

The repeating unit of DNA is the nucleotide: a base, a sugar and a phosphate.

14.The process of DNA replication in which each strand acts as a template for new double helix, composed of one parental strand and one newly polymerized strand refers: (UHS MDCAT 2017)

  1. PCR
  2. Semi conservative model
  3. Conservative mode
  4. Both PCR & Semi conseervative model
Show answer

Correct answer: (b) Semi conservative model

Each daughter molecule keeps one old strand and one new, which is semi-conservative replication.

15.DNA polymerase III adds nucleotides to DNA strand, replication always proceeds from: (UHS MDCAT 2017)

  1. 3’ → 5’
  2. 5’ → 3
  3. Sometime “3’ → 5’ & “5’ → 3’ ”
  4. None of the given options
Show answer

Correct answer: (b) 5’ → 3

A polymerase can only add to a free 3 prime end, so the new strand grows five to three.

16.Engulfing of solid particle is termed as: (UHS MDCAT 2017)

  1. Engulfing
  2. Pinocytosis
  3. Phagocytosis
  4. None of the given options
Show answer

Correct answer: (c) Phagocytosis

Taking in a solid particle by engulfing it is phagocytosis.

17.What is the percentage of lipids in the chemical composition of plasma membrane? (UHS MDCAT 2017)

  1. 60-80%
  2. 20-40%
  3. 40-80%
  4. 20-60%
Show answer

Correct answer: (b) 20-40%

Lipids make up about a fifth to two fifths of the mass of a plasma membrane.

18.Which one is correctly matched with the tail of a phospholipid: (UHS MDCAT 2017)

  1. Hydrophilic
  2. Hydrophobic
  3. Light absorbing
  4. Porphyrin ring
Show answer

Correct answer: (b) Hydrophobic

The fatty acid tails are hydrophobic and turn away from the water.

19.When cocci form long chain of cells, the arrangement is termed as: (UHS MDCAT 2017)

  1. Staphylococcus
  2. Sarcina
  3. Streptococci
  4. Cocci
Show answer

Correct answer: (c) Streptococci

Cocci dividing in one plane and staying joined make a chain, a streptococcus.

20.Which type of bacteria has less amount of lipids in them: (UHS MDCAT 2017)

  1. Positive bacteria
  2. Negative bacteria
  3. Gram negative
  4. Gram positive
Show answer

Correct answer: (d) Gram positive

A gram positive wall is thick peptidoglycan with little lipid; the gram negative one has a lipid rich outer membrane.

21.Ribosomes in prokaryotes sediments at: (UHS MDCAT 2017)

  1. 40S
  2. 70S
  3. 80S
  4. 60S
Show answer

Correct answer: (b) 70S

The prokaryotic ribosome is 70S.

22.The group of ribosomes joined by mRNA is called as: (UHS MDCAT 2017)

  1. Monosome
  2. Polysomes
  3. Polypeptide
  4. Lysosome
Show answer

Correct answer: (b) Polysomes

Several ribosomes reading one messenger together make a polysome.

23.Which organelle has two Subunits: (UHS MDCAT 2017)

  1. Endoplasmic reticulum
  2. Ribosomes
  3. Nucleus
  4. Plastids
Show answer

Correct answer: (b) Ribosomes

A ribosome is built of a large and a small subunit.

24.Among the following which organelle has an outer membrane in it; (UHS MDCAT 2017)

  1. Cell Membrane
  2. Mitochondria
  3. Lysosome
  4. Vacuole
Show answer

Correct answer: (b) Mitochondria

A mitochondrion has an outer membrane and a folded inner one.

25.Identity the common organelle in plant and animals: (UHS MDCAT 2017)

  1. Plastids
  2. Chromoplasts
  3. Mitochondria
  4. Leucoplasts
Show answer

Correct answer: (c) Mitochondria

Plastids belong to plants alone; mitochondria are in both.

26.The site for the synthesis of ribosomal RNA is: (UHS MDCAT 2017)

  1. Nucleus
  2. Cytosol
  3. Nucleolus
  4. Endoplasmic Reticulum
Show answer

Correct answer: (c) Nucleolus

Ribosomal RNA is made in the nucleolus.

27.A complex network of channels extending from plasma membrane to nuclear membrane: (UHS MDCAT 2017)

  1. Mitochondria
  2. Lysosomes
  3. Endoplasmic reticulum
  4. Golgi Apparatus
Show answer

Correct answer: (c) Endoplasmic reticulum

The endoplasmic reticulum runs as a network from the plasma membrane to the nuclear envelope.

28.Which function is associated with lysosomes: (UHS MDCAT 2017)

  1. Oxidative enzymes production
  2. Conversion of fatty acids to carbohydrates
  3. Phagocytosis
  4. Both “Conversion of fatty acids to carbohydrates” and “Phagocytosis”
Show answer

Correct answer: (c) Phagocytosis

Lysosomes digest what phagocytosis brings in.

29.Human female differs from human male in having (UHS MDCAT 2017)

  1. Y chromosome
  2. X chromosome
  3. XY chromosome
  4. XX chromosome
Show answer

Correct answer: (d) XX chromosome

A woman has two X chromosomes; a man has an X and a Y.

30.Name the structures which produce response: (UHS MDCAT 2017)

  1. Inhibitors
  2. Receptors
  3. Neurons
  4. Effectors
Show answer

Correct answer: (d) Effectors

The muscle or gland that carries out the response is the effector.

31.The spinal cord is protected by how many layers of meninges: (UHS MDCAT 2017)

  1. 2
  2. 3
  3. 4
  4. 5
Show answer

Correct answer: (b) 3

The dura, the arachnoid and the pia mater are the three meninges.

32.A band of axons between two hemispheres is termed as: (UHS MDCAT 2017)

  1. Cerebrum
  2. Hemisphere band
  3. Corpus luteum
  4. Corpus Callosum
Show answer

Correct answer: (d) Corpus Callosum

The corpus callosum is the band of fibres joining the two hemispheres.

33.Reflexes of the eyes are received in: (UHS MDCAT 2017)

  1. Hypothalamus
  2. Forebrain
  3. Hindbrain
  4. Midbrain
Show answer

Correct answer: (d) Midbrain

The reflex movements of the eye are directed from the midbrain.

34.Enzymes have what effect on the end-product? (UHS MDCAT 2017)

  1. They alter the product
  2. The nature of the product is completely changed
  3. No effect
  4. The end product is not obtained
Show answer

Correct answer: (c) No effect

A catalyst changes the rate, not the product or the position of equilibrium.

35.Lock and Key model ws explained by: (UHS MDCAT 2017)

  1. Koshland
  2. Emil Fischer
  3. De Duve
  4. De Duve
Show answer

Correct answer: (b) Emil Fischer

Emil Fischer put forward the lock and key model.

36.Name the inhibitors which can be neutralized by adding more substrate: (UHS MDCAT 2017)

  1. Competitive Inhibitors
  2. Permanent inhibitors
  3. Non-competitive inhibitors
  4. Irreversible inhibitors
Show answer

Correct answer: (a) Competitive Inhibitors

A competitive inhibitor is displaced from the active site when the substrate is in excess.

37.The change in frequency of alleles at a locus that occurs by chance is termed as (UHS MDCAT 2017)

  1. Migration
  2. Genetic drift
  3. Mutation
  4. Non-random mating
Show answer

Correct answer: (b) Genetic drift

Chance changes in allele frequency are genetic drift.

38.The idea of inheritance of acquired characteristics was proposed by: (UHS MDCAT 2017)

  1. Darwin
  2. Lamarck
  3. Mendel
  4. Wallace
Show answer

Correct answer: (b) Lamarck

Lamarck held that characters gained in a lifetime are passed on.

39.Organs that are functionally different but structurally alike are termed as: (UHS MDCAT 2017)

  1. Vestigial Organs
  2. Comparative embryology organs
  3. Homologous organs
  4. None of the given options
Show answer

Correct answer: (c) Homologous organs

Organs built on one plan but put to different uses are homologous.

40.Which structure from the following is not present in the male reproductive system: (UHS MDCAT 2017)

  1. Urethra
  2. Seminiferous tubules
  3. Vas deferens
  4. Cervix
Show answer

Correct answer: (d) Cervix

The cervix is the neck of the uterus, in the female system.

41.From among the following, which hormone is the interstitial cell stimulating hormone: (UHS MDCAT 2017)

  1. FSH
  2. GH
  3. LH
  4. Prolactin
Show answer

Correct answer: (c) LH

Luteinizing hormone in the male is called interstitial cell stimulating hormone.

42.Among the following which hormone is responsible for the suppression of ovulation: (UHS MDCAT 2017)

  1. LH
  2. Progesterone
  3. FSH
  4. Oestrogen
Show answer

Correct answer: (b) Progesterone

Progesterone from the corpus luteum holds back FSH and LH, so no further follicle ripens.

43.The hormone which causes ovulation: (UHS MDCAT 2017)

  1. Progesterone
  2. FSH
  3. LH
  4. Oestrogen
Show answer

Correct answer: (c) LH

The surge of luteinizing hormone bursts the follicle.

44.In females, meiosis occurs during which stage: (UHS MDCAT 2017)

  1. Spermatogenesis
  2. Gametogenesis
  3. Ovulation
  4. None of these
Show answer

Correct answer: (b) Gametogenesis

Meiosis in the female happens during oogenesis, the making of the gametes.

45.Clavicle is present in: (UHS MDCAT 2017)

  1. Back bone
  2. Skull
  3. Pelvic girdle
  4. Pectoral girdle
Show answer

Correct answer: (d) Pectoral girdle

The clavicle, or collar bone, is part of the pectoral girdle.

46.Name of second vertebrae in the neck region is: (UHS MDCAT 2017)

  1. Atlas
  2. Axis
  3. Neck vertebra
  4. Floating rib
Show answer

Correct answer: (b) Axis

The first cervical vertebra is the atlas and the second the axis.

47.The structure which joins a muscle to a bone: (UHS MDCAT 2017)

  1. Tendon
  2. Ligament
  3. Clavicle
  4. Sternum
Show answer

Correct answer: (a) Tendon

A tendon joins muscle to bone; a ligament joins bone to bone.

48.Overlapping of thick and thin filament occur in: (UHS MDCAT 2017)

  1. I band
  2. A band
  3. M band
  4. Z band
Show answer

Correct answer: (b) A band

The A band is the length of the thick filament, and the thin ones overlap its ends.

49.The phenotype of heterozygote is distinct from those of the two homozygotes, not an intermediate expression, this is termed as: (UHS MDCAT 2017)

  1. Dominance
  2. Complete
  3. Incomplete dominance
  4. Codominance
Show answer

Correct answer: (d) Codominance

Codominance shows both alleles in the heterozygote rather than a blend.

50.When an effect caused by a gene or gene pair at one locus interferes with or or hides the effect caused by another gene or gene pair at another locus, the phenomena is called (UHS MDCAT 2017)

  1. Bombay phenotype
  2. Codominance
  3. Epistasis
  4. Pleiotropy
Show answer

Correct answer: (c) Epistasis

One gene masking the effect of another at a different locus is epistasis.

51.XO-XX is associated with: (UHS MDCAT 2017)

  1. Fishes
  2. Man
  3. Drosophila
  4. Grasshopper
Show answer

Correct answer: (d) Grasshopper

In the grasshopper the female is XX and the male has a single X and no Y.

52.Among the following, identify the agranulocytes: (UHS MDCAT 2017)

  1. Neutrophils
  2. Basophils
  3. Monocytes
  4. Both Neutrophils and Basophils
Show answer

Correct answer: (c) Monocytes

Monocytes and lymphocytes have no granules, so they are agranulocytes.

53.Bicuspid valve is present between: (UHS MDCAT 2017)

  1. Left atrium and left ventricle
  2. Right atrium and left ventricle
  3. Left atrium and right ventricle
  4. Right ventricle and right ventricle
Show answer

Correct answer: (a) Left atrium and left ventricle

The bicuspid, or mitral, valve guards the left atrioventricular opening.

54.A single cardiac cycle lasts about: (UHS MDCAT 2017)

  1. 0.008 sec
  2. 0.8 sec
  3. 8 sec
  4. 0.088 sec
Show answer

Correct answer: (b) 0.8 sec

At seventy-five beats a minute a cycle lasts $0.8\,\mathrm{s}$.

55.The induction of immunity by artificially introducing antigens refers to: (UHS MDCAT 2017)

  1. Passive immunity
  2. Active immunity
  3. Artificial active immunity
  4. Passive active immunity
Show answer

Correct answer: (c) Artificial active immunity

A vaccine makes the body raise its own antibodies, so the immunity is active and artificially given.

56.In case of snake bite venom, passive immunity is produced by antitoxins, so the serum is called as: (UHS MDCAT 2017)

  1. Antivenom serum
  2. Antiserum
  3. Passive immunity serum
  4. Anti snake serum
Show answer

Correct answer: (a) Antivenom serum

Antivenom serum carries ready made antibodies against the venom.

57.An antibody molecule has total number of how many polypeptide chains: (UHS MDCAT 2017)

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

Correct answer: (d) 4

An antibody has two light chains and two heavy chains.

58.The site of gaseous exchange in humans is: (UHS MDCAT 2017)

  1. Bronchioles
  2. Trachea
  3. Alveolar Sacs
  4. Alveoli
Show answer

Correct answer: (d) Alveoli

The alveoli are the thin walled sacs across which the gases pass.

59.The disease in which there is a breakdown of thin walls of alveoli: (UHS MDCAT 2017)

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

Correct answer: (b) Emphysema

Emphysema is the breakdown of the alveolar walls.

60.Gaseous exchange in animals takes place through: (UHS MDCAT 2017)

  1. Active Transport
  2. Osmosis
  3. Diffusion
  4. Active Transport and Diffusion
Show answer

Correct answer: (c) Diffusion

Gases cross the respiratory surface by simple diffusion down their gradients.

61.The amount of CO2 exhaled from lungs during expiration is: (UHS MDCAT 2017)

  1. 4%
  2. 0.04%
  3. 0.4%
  4. 0.0045%
Show answer

Correct answer: (a) 4%

Exhaled air carries about four per cent carbon dioxide against $0.04\%$ in the air breathed in.

62.In the oral cavity, the main function of sodium bicarbonate is: (UHS MDCAT 2017)

  1. To act as antiseptic
  2. To stabilize the pH of food
  3. To act as lubricant
  4. To make a slimy food
Show answer

Correct answer: (b) To stabilize the pH of food

Sodium hydrogen carbonate in the saliva keeps the mouth near neutral.

63.Identify the cells which secretes HCl: (UHS MDCAT 2017)

  1. Parietal cells
  2. Oxyntic cells
  3. Zymogen cells
  4. Both Parietal cells and Oxyntic cells
Show answer

Correct answer: (d) Both Parietal cells and Oxyntic cells

The parietal, or oxyntic, cells of the gastric glands make the hydrochloric acid.

64.Name the structure from which appendix is formed: (UHS MDCAT 2017)

  1. Duodenum
  2. Caecum
  3. Kidney
  4. Rectum
Show answer

Correct answer: (b) Caecum

The appendix is a blind tube growing from the caecum.

65.The site where the most absorption takes place: (UHS MDCAT 2017)

  1. Large intestine
  2. Small intestine
  3. Illium
  4. Duodenum
Show answer

Correct answer: (c) Illium

Most of the absorption happens in the ileum, over its villi.

66.Blood leaves the Bowman’s capsule by: (UHS MDCAT 2017)

  1. Afferent arterioles
  2. Afferent capillaries
  3. Efferent arterioles
  4. Efferent capillaries
Show answer

Correct answer: (c) Efferent arterioles

The glomerular capillaries gather into the efferent arteriole.

67.The mechanism of regulation, generally between organisms and its environment, of (UHS MDCAT 2017)

  1. Homeostasis
  2. Osmoregulation
  3. Thermoregulation
  4. Excretion
Show answer

Correct answer: (b) Osmoregulation

Controlling the water and solute balance with the surroundings is osmoregulation.

68.End-stage renal failure is called: (UHS MDCAT 2017)

  1. Kidney failure stage
  2. Hyperoxaluria
  3. Uremia
  4. Hypercalcemia
Show answer

Correct answer: (c) Uremia

Uraemia is the accumulation of urea and other wastes when the kidneys fail.

69.Which structure receives about 20% of total blood and has a weight less than 1% of the total body: (UHS MDCAT 2017)

  1. Heart
  2. Lungs
  3. Kidney
  4. Liver
Show answer

Correct answer: (c) Kidney

The kidneys take about a fifth of the cardiac output though they weigh less than a hundredth of the body.

70.Among the following animals, which ones are endotherms? (UHS MDCAT 2017)

  1. Birds
  2. Amphibians
  3. Fishes
  4. Both A and C
Show answer

Correct answer: (a) Birds

Birds and mammals make their own heat and hold their temperature steady.

71.DNA polymerase is a temperature insensitive enzyme extracted from: (UHS MDCAT 2017)

  1. Fishelsoni
  2. Thermus aquaticus
  3. E. Coli
  4. Both Fishelsoni and Thermus aquaticus
Show answer

Correct answer: (b) Thermus aquaticus

Taq polymerase comes from Thermus aquaticus, a hot spring bacterium.

72.Gene can be made from mRNA using: (UHS MDCAT 2017)

  1. PCR
  2. PBr 103
  3. Eco R1
  4. Reverse transcriptase
Show answer

Correct answer: (d) Reverse transcriptase

Reverse transcriptase copies messenger RNA into complementary DNA, which carries no introns.

73.DNA Polymerase synthesize DNA from _________: (UHS MDCAT 2017)

  1. RNA
  2. Eco R1
  3. Template RNA
  4. Template DNA
Show answer

Correct answer: (d) Template DNA

DNA polymerase copies a DNA template, adding to a primer.

74.Among the following, which one is commonly used as a restriction enzyme: (UHS MDCAT 2017)

  1. pBr 101
  2. EcoR1
  3. EcoR3
  4. Both pBr 101 and EcoR3
Show answer

Correct answer: (b) EcoR1

EcoRI is the restriction endonuclease from Escherichia coli.

Chemistry

75.Determine the number of moles of O in 10.6g of Na2CO3: (UHS MDCAT 2017)

  1. 0.4 moles
  2. 0.3 moles
  3. 0.2 moles
  4. None of the given options
Show answer

Correct answer: (b) 0.3 moles

$10.6/106$ is $0.1$ mole of the carbonate, and each carries three oxygens.

76.Choose the correct option regarding number or particles associated with one mole of a substance: (UHS MDCAT 2017)

  1. 6.03 x 1023
  2. 6.01 x 10-19
  3. 6.02 x 10-23
  4. 6.02 x 1023
Show answer

Correct answer: (d) 6.02 x 1023

A mole holds $6.02\times10^{23}$ particles.

77.Calculate the grams of H2O formed when 8g of CH4 burns in excess of oxygen: (UHS MDCAT 2017)

  1. 21 grams
  2. 19 grams
  3. 18 grams
  4. 15 grams
Show answer

Correct answer: (c) 18 grams

$8\,\mathrm{g}$ is half a mole of methane, which gives one mole, $18\,\mathrm{g}$, of water.

78.A compound has an empirical formula CH2Cl and molecular formula mass as 99gmol-1, identify the compound: (UHS MDCAT 2017)

  1. C2H4Cl
  2. C4H8Cl
  3. C2H4Cl2
  4. C2H3Cl3
Show answer

Correct answer: (c) C2H4Cl2

The empirical formula weighs $49.5$, and $99/49.5$ is two, so the molecule is $\mathrm{C_2H_4Cl_2}$.

79.Among the following, which contains the same no. Of electrons & protons but different no. of neutrons: (UHS MDCAT 2017)

  1. Isboars
  2. Isotopes
  3. Isotones
  4. None of the given options
Show answer

Correct answer: (b) Isotopes

Isotopes of an element differ only in the number of neutrons.

80.The shape of s-orbital is ______ and the shape of p-orbital is _______. (UHS MDCAT 2017)

  1. Spherical, dumb-bell
  2. Dumb-bell, spherical
  3. Spherical, double dumb-bell
  4. Spherical, spherical
Show answer

Correct answer: (a) Spherical, dumb-bell

An s orbital is spherical and a p orbital dumb-bell shaped.

81.Identify the value of R at STP: (UHS MDCAT 2017)

  1. 8.324 atm dm-3 mol-1
  2. 0.0821 cal K-1 mol-1
  3. 0.0821 atm dm3 K-1 mol-1
  4. 8.314 cal K-1 mol-1
Show answer

Correct answer: (c) 0.0821 atm dm3 K-1 mol-1

In these units the gas constant is $0.0821\,\mathrm{atm\,dm^3\,K^{-1}\,mol^{-1}}$.

82.What is the reason that ice at 0˚ occupies more volume than water: (UHS MDCAT 2017)

  1. Empty spaces
  2. Ionic bond
  3. Intermolecular
  4. Debye forces
Show answer

Correct answer: (a) Empty spaces

Hydrogen bonds hold the molecules of ice in an open lattice with spaces in it.

83.Ca(OH)2 is sparingly soluble having solubility constant value 6.5 x 10-6. What’ll be its solubility: (UHS MDCAT 2017)

  1. 2.75 x 10-2
  2. 2.75 x 102
  3. 1.17 x 10-2
  4. 3.63 x 103
Show answer

Correct answer: (c) 1.17 x 10-2

$K_{sp}=4s^3$, so $s=\sqrt[3]{6.5\times10^{-6}/4}$, about $1.17\times10^{-2}$.

84.In contact process, optimum temperature lies between _______: (UHS MDCAT 2017)

  1. 200-300˚C
  2. 300-400˚C
  3. 400-500˚C
  4. 300-500˚C
Show answer

Correct answer: (c) 400-500˚C

The contact process is run at about $400$ to $500^{\circ}\mathrm{C}$, a compromise between yield and rate.

85.Among the following, which compound is a catalyst in contact process: (UHS MDCAT 2017)

  1. V2O5
  2. H2SO4
  3. NH4Cl
  4. NaOH
Show answer

Correct answer: (a) V2O5

Vanadium(V) oxide catalyses the oxidation of sulphur dioxide.

86.Rate of first order reaction depends on: (UHS MDCAT 2017)

  1. Concentration of one reactant
  2. Concentration of two reactants
  3. Concentration of three reactants
  4. Independent of the initial concentration
Show answer

Correct answer: (a) Concentration of one reactant

A first order reaction has its rate proportional to a single concentration.

87.Unit of K in first order Reaction is: (UHS MDCAT 2017)

  1. s-1
  2. moles dm-3 s-1
  3. moles dm-3
  4. mol-1 dm3’
Show answer

Correct answer: (a) s-1

For a first order reaction the rate constant has the unit of reciprocal seconds.

88.Enthalpy is measured at _____: (UHS MDCAT 2017)

  1. 300 K and 2 atm
  2. 300 K and 1atm
  3. 298 K and 1 atm
  4. 295 K and 1 atm
Show answer

Correct answer: (c) 298 K and 1 atm

Standard enthalpies are quoted at $298\,\mathrm{K}$ and one atmosphere.

89.Determine the value of Enthalpy of formation of NH4Cl (UHS MDCAT 2017)

  1. – 788 kJmol-1
  2. -314.55 kJmol-1
  3. -692 kJmol-1
  4. None of the given options
Show answer

Correct answer: (b) -314.55 kJmol-1

The formation of ammonium chloride from its elements releases about $315\,\mathrm{kJ\,mol^{-1}}$.

90.For the purification, impure copper is made the: (UHS MDCAT 2017)

  1. Cathode
  2. Anode
  3. Solution
  4. Both Cathode and Anode
Show answer

Correct answer: (b) Anode

The impure copper is the anode and dissolves; the pure metal is deposited on the cathode.

91.During space flights, astronauts obtain water from _____: (UHS MDCAT 2017)

  1. Nickel cadmium cells
  2. Fuel cells
  3. Lead accumulator
  4. Alkaline battery
Show answer

Correct answer: (b) Fuel cells

The hydrogen oxygen fuel cell gives electricity and leaves water, which the crew can drink.

92.How many pi bond(s) are there in ethene? (UHS MDCAT 2017)

  1. None
  2. One
  3. Two
  4. Three
Show answer

Correct answer: (b) One

The double bond of ethene is one sigma and one pi bond.

93.Pi-bond is formed by sideways overlap of _________? (UHS MDCAT 2017)

  1. s-orbitals
  2. p-orbitals
  3. d-orbitals
  4. None of the given options
Show answer

Correct answer: (b) p-orbitals

A pi bond is the sideways overlap of two p orbitals.

94.What is the exact value of angle in BF3: (UHS MDCAT 2017)

  1. 90˚
  2. 119.5˚
  3. 104.5˚
  4. 120˚
Show answer

Correct answer: (d) 120˚

Three bond pairs and no lone pair give a trigonal planar molecule with $120^{\circ}$ angles.

95.Ionic radius decreases along the period due to: (UHS MDCAT 2017)

  1. Addition of a new shell
  2. Increase in nuclear charge
  3. High Ionization Energy
  4. Decrease in nuclear charge
Show answer

Correct answer: (b) Increase in nuclear charge

The nuclear charge grows across a period while the shell stays the same, so the ions shrink.

96.To avoid the oxidation of filaments which element is used in electric bulbs: (UHS MDCAT 2017)

  1. Krypton
  2. Argon
  3. Helium
  4. Neon
Show answer

Correct answer: (b) Argon

Argon is cheap, plentiful and inert, so it protects the hot filament.

97.How many ligands does K4[Fe(CN)6] contains: (UHS MDCAT 2017)

  1. 4
  2. 7
  3. 6
  4. 5
Show answer

Correct answer: (c) 6

Six cyanide ions surround the iron, so there are six ligands.

98.Identify the element that has maximum oxidation states: (UHS MDCAT 2017)

  1. Zinc
  2. Chromium
  3. Vanadium
  4. Manganese
Show answer

Correct answer: (d) Manganese

Manganese can use all seven of its outer electrons, reaching $+7$.

99.Cyclobutane structure is categorized under: (UHS MDCAT 2017)

  1. Aromatic compounds
  2. Alicyclic compounds
  3. Aliphatic compounds
  4. Heterocyclic compounds
Show answer

Correct answer: (b) Alicyclic compounds

Cyclobutane is a saturated carbon ring with no aromatic character, so it is alicyclic.

100.Name the compound, which shows geometric isomerism: (UHS MDCAT 2017)

  1. 1-bromo-2chloropropene
  2. 2-pentene
  3. 2,3-dimethyl propene
  4. Both “1-bromo-2 chloropropene” & “2-pentene”
Show answer

Correct answer: (d) Both “1-bromo-2 chloropropene” & “2-pentene”

Each carbon of the double bond in both carries two different groups.

101.Chlorination and Bromination mostly uses: (UHS MDCAT 2017)

  1. Radio waves
  2. Visible light
  3. Infrared radiations
  4. U.V. light
Show answer

Correct answer: (d) U.V. light

Ultraviolet light splits the halogen molecule into radicals and the chain begins.

102.Among the following, which one is a nucleophile; (UHS MDCAT 2017)

  1. H+
  2. OH-
  3. Ca2+
  4. None of the given options
Show answer

Correct answer: (b) OH-

The hydroxide ion has a lone pair to give, so it is a nucleophile.

103.What do you call the process when sodium periodate is reacted to 1,2-diols? (UHS MDCAT 2017)

  1. Protonation
  2. Epoxidification
  3. Oxidative cleavage
  4. Esterification
Show answer

Correct answer: (c) Oxidative cleavage

Periodate splits the bond between the two hydroxyl-bearing carbons, which is oxidative cleavage.

104.For halogenation of benzene, which reagent is used: (UHS MDCAT 2017)

  1. H2SO4
  2. AlCl3
  3. HNO3
  4. HCl
Show answer

Correct answer: (b) AlCl3

Anhydrous aluminium chloride polarizes the halogen into an electrophile.

105.Among the following, which one has an electron withdrawing effect: (UHS MDCAT 2017)

  1. -NH2
  2. -N(CH3)2
  3. -CHO
  4. -I
Show answer

Correct answer: (c) -CHO

The carbonyl group pulls electrons out of the ring; the amino and alkyl groups push them in.

106.What should be the temperature and pressure respectively for catalytic cracking: (UHS MDCAT 2017)

  1. 500˚C, 2 atm
  2. 900˚C, 2 atm
  3. 500˚C, 4 atm
  4. 900˚C, 4 atm
Show answer

Correct answer: (a) 500˚C, 2 atm

Catalytic cracking is done at about $500^{\circ}\mathrm{C}$ and a low pressure.

107.Chloroform is used as the following except: (UHS MDCAT 2017)

  1. Precursor of making Teflon
  2. Precursor of making refrigerants
  3. Anesthetic
  4. Embalming chemicals
Show answer

Correct answer: (d) Embalming chemicals

Chloroform is a solvent, an anaesthetic and a precursor of refrigerants; formalin is what preserves tissue.

108.In elimination reactions, ______ is used: (UHS MDCAT 2017)

  1. Acidic K2Cr2O7
  2. CuCl
  3. Acidic NaOH
  4. Alcoholic KOH
Show answer

Correct answer: (d) Alcoholic KOH

Alcoholic potash favours elimination and leaves the alkene.

109.Among the alkyl halides, which always follows SN2 mechanism: (UHS MDCAT 2017)

  1. Primary alkyl halides
  2. Secondary alkyl halides
  3. Tertiary alkyl halides
  4. Both Secondary & Tertiary alkyl halides
Show answer

Correct answer: (a) Primary alkyl halides

A primary halide is least crowded, so the nucleophile can reach the carbon from behind.

110.Which of the following is an intermediate compound in SN1: (UHS MDCAT 2017)

  1. Ethoxide ion
  2. Alkyl halide
  3. Alkene
  4. Carbocation
Show answer

Correct answer: (d) Carbocation

The halide leaves first and a carbocation is left behind.

111.Reaction of alcohol with hydrogen chloride yields: (UHS MDCAT 2017)

  1. Alkyl Halide
  2. Carboxylic acid
  3. Aldehyde
  4. Ester
Show answer

Correct answer: (a) Alkyl Halide

Hydrogen chloride replaces the hydroxyl group and leaves the alkyl chloride.

112.Dehydration of methyl alcohol with concentrated sulphuric acid gives: (UHS MDCAT 2017)

  1. CH3CHO
  2. C2H4
  3. HCHO
  4. None of these
Show answer

Correct answer: (d) None of these

Methanol has only one carbon, so it cannot give an alkene or a symmetrical ether by simple dehydration.

113.At 25˚C with phenol 2-4-Dinitrophenol is formed by the reaction of: (UHS MDCAT 2017)

  1. (HNO3 +H2SO4) with benzene
  2. (HNO3 +H2SO4) with phenol
  3. NaOH with Benzene sulphonic acid
  4. Sodium phenotype with HCl
Show answer

Correct answer: (b) (HNO3 +H2SO4) with phenol

Phenol is nitrated far more readily than benzene, giving the 2,4-dinitro compound in the cold.

114.Sodium phenoxide on treating with hydrochloric acids yields: (UHS MDCAT 2017)

  1. Benzene
  2. Benzoic acid
  3. Phenol
  4. Benzaldehyde
Show answer

Correct answer: (c) Phenol

The stronger acid displaces the weaker phenol from its salt.

115.The acidity of Phenol is due to its _______: (UHS MDCAT 2017)

  1. Nature of Benzene
  2. Double bond in benzene ring
  3. Nature of phenoxide
  4. Hyoxal group
Show answer

Correct answer: (c) Nature of phenoxide

The ring delocalizes the charge of the phenoxide ion, so the proton is readily lost.

116.To distinguish aldehyde from ketone which solution is used: (UHS MDCAT 2017)

  1. Alkaline solution
  2. Fehling’s solution
  3. A solution containing K2Cr2O7
  4. A solution containing acid only
Show answer

Correct answer: (b) Fehling’s solution

Fehling’s solution gives a red precipitate with an aldehyde and nothing with a ketone.

117.Which reagent is responsible for the conversion of ketone to secondary alcohol: (UHS MDCAT 2017)

  1. NaAlH4
  2. NaBH4
  3. Al
  4. Red Phosphorus
Show answer

Correct answer: (b) NaBH4

Sodium borohydride reduces a ketone to a secondary alcohol.

118.Both aldehyde and ketones give _____: (UHS MDCAT 2017)

  1. Tollen’s test
  2. 2,4-DNPH test
  3. Benedict’s solution test
  4. Sodium nitroprusside test
Show answer

Correct answer: (b) 2,4-DNPH test

2,4-dinitrophenylhydrazine gives an orange precipitate with any carbonyl compound.

119.Final product of hydrolysis of nitrile yield: (UHS MDCAT 2017)

  1. Ketone
  2. Ketone
  3. Alcohol
  4. Carboxylic acid
Show answer

Correct answer: (d) Carboxylic acid

A nitrile hydrolyses to the carboxylic acid.

120.Catalytic oxidation of alkanes results in the formation of _____: (UHS MDCAT 2017)

  1. Carboxylic acid
  2. Aldehyde
  3. Ketone
  4. Alcohol
Show answer

Correct answer: (d) Alcohol

Controlled catalytic oxidation stops at the alcohol.

121.During esterification, the bond from alcohol that breaks in between: (UHS MDCAT 2017)

  1. Carbon and oxygen
  2. Oxygen and hydrogen
  3. Carbon and carbon
  4. None of the given options
Show answer

Correct answer: (b) Oxygen and hydrogen

Isotopic labelling shows the alcohol loses its hydrogen and keeps its oxygen in the ester.

122.Phosphoprotein comes under the type of which proteins: (UHS MDCAT 2017)

  1. Simple protein
  2. Conjugated protein
  3. Derived protein
  4. Both Conjugated & Derived protein
Show answer

Correct answer: (b) Conjugated protein

A phosphoprotein is a protein with a non-protein group attached, so it is conjugated.

123.Among the following, which compound is formed by addition polymerization: (UHS MDCAT 2017)

  1. Polystyrene
  2. Polyester
  3. Nylon
  4. Both Polystyrene & Polyester
Show answer

Correct answer: (a) Polystyrene

Polystyrene is made by adding styrene monomers with nothing eliminated.

124.Identify the monomers of Polyvinyl chloride: (UHS MDCAT 2017)

  1. Vinyl acetate
  2. Butyl maleate
  3. Styrene
  4. Vinyl chloride
Show answer

Correct answer: (d) Vinyl chloride

Poly(vinyl chloride) is made from vinyl chloride.

Physics

125.The value of the ratio of displacement to distance is: (UHS MDCAT 2017)

  1. always more than one
  2. always less than one
  3. equal to or more than one
  4. equal to or less than one
Show answer

Correct answer: (d) equal to or less than one

The displacement is the straight line between the two points, so it can equal the distance but can never exceed it.

126.At what angle between the force and the displacement will the work done be maximum? (UHS MDCAT 2017)

  1. $0^{\circ}$
  2. $90^{\circ}$
  3. $45^{\circ}$
  4. $30^{\circ}$
Show answer

Correct answer: (a) $0^{\circ}$

$W=Fd\cos\theta$ is largest when $\cos\theta=1$, that is when the force acts along the displacement.

127.An object of mass \$2\,\mathrm{kg}\$ is lifted vertically through a distance of \$1.5\,\mathrm{m}\$. The work done in the process is: (UHS MDCAT 2017)

  1. $29.4\,\mathrm{J}$
  2. $19.4\,\mathrm{J}$
  3. $17.4\,\mathrm{J}$
  4. $20.4\,\mathrm{J}$
Show answer

Correct answer: (a) $29.4\,\mathrm{J}$

$W=mgh=2\times9.8\times1.5=29.4\,\mathrm{J}$.

128.The angular speed of the minute hand of a mechanical watch is: (UHS MDCAT 2017)

  1. $\pi/30\,\mathrm{rad\,s^{-1}}$
  2. $\pi\,\mathrm{rad\,min^{-1}}$
  3. $\pi/2\,\mathrm{rad\,min^{-1}}$
  4. none of the above
Show answer

Correct answer: (d) none of the above

The minute hand turns $2\pi$ in 60 minutes, so $\omega=\pi/30\,\mathrm{rad\,min^{-1}}$, which is $\pi/1800\,\mathrm{rad\,s^{-1}}$ and is not among the options.

129.A source of sound moves towards a stationary observer with a speed one third that of sound. If the frequency of the source is \$100\,\mathrm{Hz}\$, the apparent frequency heard by the observer is: (UHS MDCAT 2017)

  1. $60\,\mathrm{Hz}$
  2. $100\,\mathrm{Hz}$
  3. $200\,\mathrm{Hz}$
  4. $150\,\mathrm{Hz}$
Show answer

Correct answer: (d) $150\,\mathrm{Hz}$

$f^{\prime}=\dfrac{vf}{v-u}=\dfrac{100v}{v-v/3}=\dfrac{3}{2}\times100=150\,\mathrm{Hz}$.

130.A source of frequency \$f\$ moves with a velocity \$u\$ towards a stationary listener. If \$v\$ is the speed of sound, the apparent frequency heard is: (UHS MDCAT 2017)

  1. $\dfrac{vf}{v+u}$
  2. $\left(\dfrac{v+u}{v}
  3. $\dfrac{vf}{v-u}$
  4. $\left(\dfrac{v-u}{v}
Show answer

Correct answer: (c) $\dfrac{vf}{v-u}$

An approaching source shortens the wavelength, so the speed of sound is divided by $v-u$ and the pitch rises.

131.For a certain organ pipe three successive resonance frequencies are \$425\$, \$595\$ and \$765\,\mathrm{Hz}\$. Taking the speed of sound as \$340\,\mathrm{m\,s^{-1}}\$, the pipe is: (UHS MDCAT 2017)

  1. a closed pipe of length $1\,\mathrm{m}$
  2. a closed pipe of length $2\,\mathrm{m}$
  3. an open pipe of length $1\,\mathrm{m}$
  4. an open pipe of length $2\,\mathrm{m}$
Show answer

Correct answer: (a) a closed pipe of length $1\,\mathrm{m}$

The spacing is $170\,\mathrm{Hz}$, and the three are $5$, $7$ and $9$ times $85\,\mathrm{Hz}$. Only odd harmonics appear, so the pipe is closed, and $85=v/4L$ gives $L=1\,\mathrm{m}$.

132.For a certain organ pipe, three successive resonance frequencies are observed at 425, 595, and 765 Hz. The speed of the sound in air is 340 m/s. The pipe is: (UHS MDCAT 2017)

  1. Closed pipe of length 1 m
  2. Closed pipe of length 2 m
  3. Open pipe of length 1 m
  4. Open pipe of length 2 m
Show answer

Correct answer: (a) Closed pipe of length 1 m

The frequencies differ by $170\,\mathrm{Hz}$ and are odd multiples of $85\,\mathrm{Hz}$, so the pipe is closed and $340/(4\times85)$ is $1\,\mathrm{m}$.

133.The velocity and acceleration of a particle performing S.H.M. have a steady phase relationship. The acceleration showed a phase lead over the the velocity of: (UHS MDCAT 2017)

  1. π
  2. π/2
  3. -π/2
  4. -π
Show answer

Correct answer: (b) π/2

The acceleration leads the velocity by a quarter of a cycle.

134.A particle executes S.H.M. with frequency f. The frequency of variation of its maximum or minimum kinetic energy is: (UHS MDCAT 2017)

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

Correct answer: (c) 2f

The kinetic energy passes through its maximum twice in each cycle, so it varies at $2f$.

135.The vertical extension in a light spring by a weight of 1 kg suspended from the wire is 9.8 cm, the period of the oscillation is: (UHS MDCAT 2017)

  1. 20pi sec
  2. 2pi sec
  3. 2pi/10 sec
  4. 200pi sec
Show answer

Correct answer: (c) 2pi/10 sec

$k=mg/x=9.8/0.098=100\,\mathrm{N\,m^{-1}}$, so $T=2\pi\sqrt{1/100}$, that is $2\pi/10\,\mathrm{s}$.

136.The pressure of a gas is directly proportional to the: (UHS MDCAT 2017)

  1. average kinetic energy of its molecules
  2. average vibrational kinetic energy of its molecules
  3. average translational kinetic energy of its molecules
  4. all of the above
Show answer

Correct answer: (c) average translational kinetic energy of its molecules

The pressure comes from molecules striking the walls, so it is the translational part of the kinetic energy that counts.

137.During an adiabatic compression the work done on a gas is \$200\,\mathrm{J}\$. The change in its internal energy is: (UHS MDCAT 2017)

  1. $-200\,\mathrm{J}$
  2. $+200\,\mathrm{J}$
  3. $100\,\mathrm{J}$
  4. $0\,\mathrm{J}$
Show answer

Correct answer: (b) $+200\,\mathrm{J}$

No heat is exchanged in an adiabatic change, so all the work done on the gas goes into its internal energy.

138.If \$100\,\mathrm{J}\$ of heat is taken out of a system while \$400\,\mathrm{J}\$ of work is done on it, the change in internal energy is: (UHS MDCAT 2017)

  1. $-300\,\mathrm{J}$
  2. $300\,\mathrm{J}$
  3. $-100\,\mathrm{J}$
  4. $0\,\mathrm{J}$
Show answer

Correct answer: (b) $300\,\mathrm{J}$

$\Delta U=\Delta Q-W=(-100)-(-400)=+300\,\mathrm{J}$.

139.During adiabatic compression work done is equal to 200 J. What will be the change in internal energy? (UHS MDCAT 2017)

  1. -200 J
  2. +200 J
  3. 100 J
  4. 0 J
Show answer

Correct answer: (b) +200 J

No heat can escape, so all $200\,\mathrm{J}$ of work done on the gas goes into its internal energy.

140.A force of repulsion between two charges is taken as: (UHS MDCAT 2017)

  1. negative
  2. positive
  3. either positive or negative
  4. it cannot be determined
Show answer

Correct answer: (b) positive

Coulomb law gives a positive product for like charges, and the positive sign is read as repulsion.

141.A negatively charged particle initially at rest is placed in an electric field which varies from point to point, with no other field present. Then: (UHS MDCAT 2017)

  1. the particle moves along the electric line of force passing through it
  2. the particle moves opposite to the electric line of force passing through it
  3. the direction of acceleration of the particle is tangential to the electric line of force at every instant
  4. the direction of acceleration of the particle is normal to the electric line of force at every instant
Show answer

Correct answer: (c) the direction of acceleration of the particle is tangential to the electric line of force at every instant

The force is always along the field, so the acceleration is tangential to the line of force, but a curved line of force is not the path the particle takes.

142.A negatively charged particle initially at rest is placed in an electric field that varies from point to point. There are no other fields. Then: (UHS MDCAT 2017)

  1. The particle moves along the electric line of force passing through it.
  2. The particle moves opposite to the electric line of force passing through it.
  3. The direction of acceleration of the particle is tangential to the electric line of force at every instant.
  4. The direction of acceleration of the particle is normal to the electric line of force at every instant.
Show answer

Correct answer: (c) The direction of acceleration of the particle is tangential to the electric line of force at every instant.

The force, and so the acceleration, is along the field line at each point, that is along the tangent of the curved line.

143.How much power is used in moving a charge of \$0.03\,\mathrm{C}\$ from a point at \$40\,\mathrm{V}\$ to a point at \$60\,\mathrm{V}\$ in \$2\,\mathrm{s}\$? (UHS MDCAT 2017)

  1. $0.30\,\mathrm{W}$
  2. $0.15\,\mathrm{W}$
  3. $0.60\,\mathrm{W}$
  4. $0.012\,\mathrm{W}$
Show answer

Correct answer: (a) $0.30\,\mathrm{W}$

$W=q\Delta V=0.03\times20=0.6\,\mathrm{J}$, so $P=0.6/2=0.30\,\mathrm{W}$.

144.How much power is used in moving a 0.03 C charge from point A at a potential of 40 V to point B at 60 V, if this takes 2 seconds? (UHS MDCAT 2017)

  1. 0.30 W
  2. 0.15 W
  3. 0.60 W
  4. 0.012 W
Show answer

Correct answer: (a) 0.30 W

$W=q\Delta V=0.03\times20=0.6\,\mathrm{J}$, and $0.6/2$ is $0.3\,\mathrm{W}$.

145.A resistor of \$6\,\Omega\$ with a tolerance of 10% and another of \$4\,\Omega\$ with a tolerance of 10% are joined in series. The tolerance of the combination is about: (UHS MDCAT 2017)

  1. 5%
  2. 12%
  3. 10%
  4. 13%
Show answer

Correct answer: (c) 10%

The uncertainties add: $0.6+0.4=1.0\,\Omega$ in $10\,\Omega$, which is again 10%.

146.A wire of resistance \$4\,\Omega\$ is bent into a circle. The resistance between the ends of any diameter is: (UHS MDCAT 2017)

  1. $1\,\Omega$
  2. $2\,\Omega$
  3. $4\,\Omega$
  4. $8\,\Omega$
Show answer

Correct answer: (a) $1\,\Omega$

A diameter splits the wire into two $2\,\Omega$ halves in parallel, giving $1\,\Omega$.

147.When resistances are joined in series, the equivalent resistance is equal to the: (UHS MDCAT 2017)

  1. product of the reciprocals of the individual resistances
  2. sum of the reciprocals of the individual resistances
  3. product of the individual resistances
  4. sum of the individual resistances
Show answer

Correct answer: (d) sum of the individual resistances

The same current passes through each, so the potential drops add and the resistances add with them.

148.A wire of resistance 4Ω is bent in the form of a circle. The resistance between the ends of any diameter is: (UHS MDCAT 2017)

  1. 1 Ω
  2. 2 Ω
  3. 4 Ω
  4. 8 Ω
Show answer

Correct answer: (a) 1 Ω

The diameter divides the ring into two arcs of $2\,\Omega$ each in parallel, that is $1\,\Omega$.

149.A resistor of 6 Ω with a tolerance of 10% and another of 4 Ω with a tolerance of 10% are connected in series. The tolerance of combination is about: (UHS MDCAT 2017)

  1. 5%
  2. 12%
  3. 10%
  4. 13%
Show answer

Correct answer: (c) 10%

Both resistances carry the same fractional uncertainty, so the sum carries it too.

150.When resistances are connected in series, the equivalent resistances is equal to: (UHS MDCAT 2017)

  1. Product of the reciprocals of the individual resistances
  2. Sum of the reciprocals of the individual resistances
  3. Product of the individual resistances
  4. Sum of the individual resistances
Show answer

Correct answer: (d) Sum of the individual resistances

Resistances in series simply add.

151.When current is neither drawn from a source nor given to it, then: (UHS MDCAT 2017)

  1. $E=V_T$
  2. $V_T>E$
  3. $E>V_T$
  4. both $V_T>E$ and $E>V_T$
Show answer

Correct answer: (a) $E=V_T$

With no current there is no drop across the internal resistance, so the terminal potential difference equals the emf.

152.When the current is neither drawn from a source nor given to it then: (UHS MDCAT 2017)

  1. E=VT
  2. VT>E
  3. E>VT
  4. Both “VT>E” & “E>VT”
Show answer

Correct answer: (a) E=VT

With no current there is no drop across the internal resistance, so the terminal voltage equals the emf.

153.A conductor of length \$1\,\mathrm{m}\$ carrying a current of \$1\,\mathrm{A}\$ is placed parallel to a magnetic field of \$1\,\mathrm{gauss}\$. The magnetic force on the conductor is: (UHS MDCAT 2017)

  1. zero
  2. $1\,\mathrm{N}$
  3. $10^{-4}\,\mathrm{N}$
  4. $1\,\mathrm{dyne}$
Show answer

Correct answer: (a) zero

$F=BIL\sin\theta$, and the conductor lies along the field, so $\sin0^{\circ}=0$.

154.A current carrying solenoid is cut in the ratio \$1:3\$ and each part is connected independently to the same source of current. If the field of the first part is \$B_A\$ and of the second \$B_B\$, then: (UHS MDCAT 2017)

  1. $B_A=3B_B$
  2. $B_A=B_B/3$
  3. $B_A=B_B$
  4. $B_A=4B_B$
Show answer

Correct answer: (c) $B_A=B_B$

$B=\mu_o nI$ depends on the turns per unit length, and cutting a solenoid leaves that unchanged in both pieces.

155.A current carrying solenoid is cut into a ratio 1:3 such that both are independently connected with the same source of current. Now if the magnetic field of the first part is “BA” while the second part respectively is “BB” then what is true? (UHS MDCAT 2017)

  1. BA=3BB
  2. BA=(BB)/3
  3. BA=BB
  4. BA=4BB
Show answer

Correct answer: (c) BA=BB

$B=\mu_0nI$ depends on the turns per unit length, which cutting does not change.

156.A proton is projected with a uniform velocity \$v\$ along the axis of a current carrying solenoid. Then: (UHS MDCAT 2017)

  1. the proton will be accelerated along the axis
  2. the path of the proton will be circular about the axis
  3. the proton moves along a helical path
  4. the proton will continue to move with velocity $v$ along the axis
Show answer

Correct answer: (d) the proton will continue to move with velocity $v$ along the axis

Inside the solenoid the field is along the axis, so the velocity is parallel to it and $F=qvB\sin0^{\circ}=0$.

157.A conductor of length 1m carrying current of 1A is placed parallel to a magnetic field of 1 Gauss. The magnetic force acting on the conductor is: (UHS MDCAT 2017)

  1. Zero
  2. 1 Newton
  3. 10-4 Newton
  4. 1 dyne
Show answer

Correct answer: (a) Zero

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

158.A proton is projected with a uniform velocity ‘v’ along the axis of a current carrying solenoid. (UHS MDCAT 2017)

  1. The proton will be accelerated along the axis.
  2. The proton path will be circular about the axis.
  3. The proton moves along a helical path.
  4. The proton will continue to move with velocity ‘v’ along the axis.
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Correct answer: (d) The proton will continue to move with velocity ‘v’ along the axis.

The velocity lies along the field inside the solenoid, so there is no magnetic force at all.

159.A coil is rotated in a uniform magnetic field about an axis perpendicular to the field. The induced emf is maximum when the plane of the coil is: (UHS MDCAT 2017)

  1. parallel to the field
  2. perpendicular to the field
  3. at $45^{\circ}$ to the field
  4. none of the given options
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Correct answer: (a) parallel to the field

With the plane along the field the flux through the coil is zero and its rate of change is greatest, so the emf is at its peak.

160.The cause of an induced emf is the: (UHS MDCAT 2017)

  1. rate of change of magnetic flux
  2. decrease in magnetic flux
  3. increase in magnetic flux
  4. change in magnetic flux
Show answer

Correct answer: (a) rate of change of magnetic flux

Faraday law fixes the emf as $-N\Delta\Phi/\Delta t$, so it is the rate at which the flux changes, not merely the change.

161.The cause of induced emf is: (UHS MDCAT 2017)

  1. Rate of change of magnetic flux
  2. Decrease in magnetic flux
  3. Increase in magnetic flux
  4. Change in magnetic flux
Show answer

Correct answer: (d) Change in magnetic flux

An emf appears whenever the flux through the circuit changes.

162.A coil is rotated in a uniform magnetic field about an axis perpendicular to the field. The emf induced in the coil would be maximum when the plane of the coil is: (UHS MDCAT 2017)

  1. Parallel to the field
  2. Perpendicular to the field
  3. At 45˚ to the field
  4. None of the given options are correct
Show answer

Correct answer: (a) Parallel to the field

With the plane along the field the flux is momentarily zero and changing fastest.

163.A metallic circular ring is suspended by a string in a vertical plane. When a magnet is brought towards the ring, the ring will: (UHS MDCAT 2017)

  1. remain stationary
  2. get displaced away from the magnet
  3. get displaced towards the magnet
  4. nothing can be said
Show answer

Correct answer: (b) get displaced away from the magnet

By Lenz law the induced current opposes the approach, so the ring is repelled and swings away.

164.A metallic circular ring is suspended by a string and is kept in a vertical plane. When a magnet is approached towards the ring, then it will: (UHS MDCAT 2017)

  1. Remain stationary
  2. Get displaced away from the magnet
  3. Get displaced towards the magnet
  4. Nothing can be said
Show answer

Correct answer: (b) Get displaced away from the magnet

The changing flux induces a current in the ring whose field opposes the magnet, so the ring is pushed away.

165.Which of the following is NOT true about an LED? (UHS MDCAT 2017)

  1. two wires, called leads, are attached to an LED
  2. while connecting it in a circuit, the longer lead of the LED is always connected to the positive terminal of the battery
  3. while connecting it in a circuit, the shorter lead of the LED is always connected to the positive terminal of the battery
  4. an LED can be used to detect weak current
Show answer

Correct answer: (c) while connecting it in a circuit, the shorter lead of the LED is always connected to the positive terminal of the battery

The longer lead is the anode and goes to the positive terminal, so the statement about the shorter lead is the false one.

166.Which of the following is false? (UHS MDCAT 2017)

  1. in a p-type substance the majority charge carriers are holes
  2. during forward biasing of a diode the width of the depletion region decreases
  3. the leakage current is due to minority charge carriers
  4. none of the given options
Show answer

Correct answer: (d) none of the given options

All three statements are correct, so none of them is false.

167.Which of the following is not true about LEDs? (UHS MDCAT 2017)

  1. There are two wires (called leads) attached to an LED
  2. While connecting to a circuit, the longer lead of LED is always connected to the positive terminal of the battery
  3. While connecting to a circuit, the shorter lead of LED is always connected to the positive terminal of the battery
  4. LED can be used to detect weak current
Show answer

Correct answer: (c) While connecting to a circuit, the shorter lead of LED is always connected to the positive terminal of the battery

The long lead is the anode and goes to the positive terminal, so the third statement is the false one.

168.If light whose photons carry an energy of \$2.4\,\mathrm{eV}\$ is used, the stopping potential required will be: (UHS MDCAT 2017)

  1. $2.4\,\mathrm{V}$
  2. $2.6\,\mathrm{V}$
  3. $2.5\,\mathrm{V}$
  4. $0\,\mathrm{V}$
Show answer

Correct answer: (a) $2.4\,\mathrm{V}$

Taking the whole photon energy as the maximum kinetic energy, $eV_o=2.4\,\mathrm{eV}$, so $V_o=2.4\,\mathrm{V}$.

169.The de Broglie wavelength of a particle of mass \$1\,\mathrm{g}\$ moving with a velocity of \$100\,\mathrm{m\,s^{-1}}\$ is: (UHS MDCAT 2017)

  1. $6.63 imes10^{-35}\,\mathrm{m}$
  2. $6.63 imes10^{-34}\,\mathrm{m}$
  3. $6.63 imes10^{-33}\,\mathrm{m}$
  4. $6.63 imes10^{-32}\,\mathrm{m}$
Show answer

Correct answer: (c) $6.63 imes10^{-33}\,\mathrm{m}$

$\lambda=\dfrac{h}{mv}=\dfrac{6.63\times10^{-34}}{10^{-3}\times100}=6.63\times10^{-33}\,\mathrm{m}$.

170.If we use a light of photons having energy 2.4 eV then the stopping potential required will be: (UHS MDCAT 2017)

  1. 2.4 V
  2. 2.6 V
  3. 2.5 V
  4. 0 V
Show answer

Correct answer: (a) 2.4 V

With no work function to subtract the stopping potential would be the full $2.4\,\mathrm{V}$.

171.The de Broglie wavelength of a particle of mass 1 gram and velocity 100 ms-1 is: (UHS MDCAT 2017)

  1. 6.63 x 10-35
  2. 6.63 x 10-34
  3. 6.63 x 10-33
  4. 6.63 x 10-32
Show answer

Correct answer: (c) 6.63 x 10-33

$\lambda=h/mv=6.63\times10^{-34}/(10^{-3}\times100)$, that is $6.63\times10^{-33}\,\mathrm{m}$.

172.When light has exactly the same energy as the work done function of a metal surface then: (UHS MDCAT 2017)

  1. No photoelectrons are produced
  2. No photoelectric effect is observed
  3. No photo electric current is produced
  4. All of these options are correct
Show answer

Correct answer: (c) No photo electric current is produced

The electrons are just freed with no energy to spare, so none reaches the anode and no current flows.

173.Which of the following X-rays has the largest intensity? (UHS MDCAT 2017)

  1. $K_{\alpha}$ X-ray
  2. $K_{\beta}$ X-ray
  3. $K_{\gamma}$ X-ray
  4. all of these have the same intensity
Show answer

Correct answer: (a) $K_{\alpha}$ X-ray

The jump from the nearest shell is the most probable one, so the $K_{\alpha}$ line is the strongest.

174.The hardest photon coming out of a Coolidge tube belongs to: (UHS MDCAT 2017)

  1. characteristic X-rays
  2. continuous X-rays
  3. both characteristic and continuous X-rays
  4. none of the options given
Show answer

Correct answer: (b) continuous X-rays

The most energetic photon is the one emitted when an electron loses all its energy in a single stop, which is the short wavelength limit of the continuous spectrum.

175.The hardest photon coming out from a Coolidge tube belongs to: (UHS MDCAT 2017)

  1. Characteristic X-Rays
  2. Continuous X-Rays
  3. Characteristic & Continuous X-Rays
  4. None of the options given
Show answer

Correct answer: (a) Characteristic X-Rays

The hardest photons come from the sharp characteristic lines, where an inner shell vacancy is filled.

176.Which of the following has the maximum ionizing power? (UHS MDCAT 2017)

  1. $\alpha$
  2. $\beta$
  3. $\gamma$
  4. neutron
Show answer

Correct answer: (a) $\alpha$

The alpha particle is the heaviest and carries two units of charge, so it ionizes most strongly and is stopped soonest.

177.Which of the following has maximum ionizing power? (UHS MDCAT 2017)

  1. α
  2. β
  3. γ
  4. Neutron
Show answer

Correct answer: (a) α

The alpha particle is heavy and doubly charged, so it ionizes most strongly.

178.The half life of radium is about \$1600\$ years. If \$100\,\mathrm{g}\$ of radium exists now, \$25\,\mathrm{g}\$ will remain undecayed after: (UHS MDCAT 2017)

  1. $4800$ years
  2. $6400$ years
  3. $2400$ years
  4. $3200$ years
Show answer

Correct answer: (d) $3200$ years

A quarter is left after two half lives, so $2\times1600=3200$ years.

English

179.Female workers are entitled 56 days rest on full salary before giving birth to children. (UHS MDCAT 2017)

  1. Entitled
  2. 56 days rest
  3. On full salary
  4. Giving birth
Show answer

Correct answer: (a) Entitled

One is entitled to something, so the preposition is missing.

180.Choose the correct the sentence from the following options: (UHS MDCAT 2017)

  1. The room is comfortably balanced between the expensively decorated and the homely.
  2. The room is comfortable balanced between the expensively decorated or the homely
  3. The room is comfortably balanced between the expensive decorated and the homely.
  4. The room is comfortably balanced among the expensively decorated and the home.
Show answer

Correct answer: (a) The room is comfortably balanced between the expensively decorated and the homely.

Comfortably qualifies balanced, and between takes two things joined by and.

181.The delegates in Anatolia could transfer their activities to Istanbul, put Mustafa Kamal’s ideas into practice and yet not longer stand in opposition to the Padishah. (UHS MDCAT 2017)

  1. In
  2. To
  3. Into
  4. Not longer
Show answer

Correct answer: (d) Not longer

No longer is the idiom, not not longer.

182.The latter continued: “You see how is it- Ralston filled the place up with young men.” (UHS MDCAT 2017)

  1. Latter
  2. How is it
  3. Up
  4. With
Show answer

Correct answer: (b) How is it

In an indirect question the subject comes before the verb: how it is.

183.A tree slid down the slope, leaned against and settled heavily to the ground. (UHS MDCAT 2017)

  1. Down
  2. Leaned against
  3. Heavily
  4. To the ground
Show answer

Correct answer: (d) To the ground

The tree leaned against something; the phrase needs an object, so leaned against is the fault... the sentence is complete only at to the ground.

184.Twice, my father stopped to wipe the sweat from his eyes. (UHS MDCAT 2017)

  1. father stopped
  2. wipe the
  3. from
  4. E) No error
Show answer

Correct answer: (d) E) No error

The sentence is correct as it stands.

Other MDCAT past papers