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UPSC Prelims 2001

147 questions, in the order they were asked.

2001 · Q106Science & TechnologyEnergy & Environmentmoderate

Consider the following statements: In a nuclear reactor, self-sustained chain reaction is possible, because I. More neutrons are released in each of the fission reactions. II. The neutrons immediately take part in the fission process. III. The fast neutrons are slowed down by Graphite. IV. Every neutron released in the fission reaction initiates further fission. Which of these statements are correct?

  1. (a)I, II and III
  2. (b)I and III
  3. (c)II and IV
  4. (d)II, III and IV
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Official answer(b) I and III

2001 · Q110Science & TechnologyPhysicsmoderate

Consider the following statements: A simple pendulum is set into oscillation. Then I. The acceleration is zero when the bob passes through the mean position. II. In each cycle the bob attains a given velocity twice. III. Both acceleration and velocity of the bob are zero when it reaches its extreme position during its oscillation. IV. The amplitude of oscillation of the simple pendulum decreases with time. Which of these statements are correct?

  1. (a)I and II
  2. (b)III and IV
  3. (c)I, II and IV
  4. (d)II, III and IV
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Official answer(c) I, II and IV

2001 · Q114Indian EconomyNational Income & Economic Growthmoderate

The following table shows the percentage change in the consumption of electricity by five towns P, Q, R, S, T from 1986 to 1988: Town Per cent change from 1986 to 1987 From 1987 to 1988 P +8 −18 Q +15 −11 R +6 +9 S −7 −5 T +13 −6 If town T consumed 500,000 units in 1986, how much did it consume in 1988?

  1. (a)371,000 units
  2. (b)531,100 units
  3. (c)551,100 units
  4. (d)571,100 units
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Official answer(b) 531,100 units

2001 · Q116Science & TechnologyChemistryeasy

Assertion (A): A chemical reaction becomes faster at higher temperatures. Reason (R): At higher temperatures, molecular motion becomes more rapid. Which of the following is correct?

  1. (a)Both A and R are individually true and R is the correct explanation of A
  2. (b)Both A and R are individually true but R is NOT a correct explanation of A
  3. (c)A is true but R is false
  4. (d)A is false but R is true
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Official answer(a) Both A and R are individually true and R is the correct explanation of A

2001 · Q121Science & TechnologyChemistrymoderate

Consider the following statements with reference to the Periodic Table of chemical elements: I. Ionisation potential gradually decreases along a period. II. In a group of elements, electron affinity decreases as the atomic weight increases. III. In a given period, electronegativity decreases as the atomic number increases. Which of these statement(s) is/are correct?

  1. (a)I only
  2. (b)II only
  3. (c)I and III
  4. (d)II and III
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Official answer(b) II only

2001 · Q124Science & TechnologyBiotechnology & Geneticsmoderate

Assertion (A): Scientists can cut apart and paste together DNA molecules at will, regardless of the source of the molecules. Reason (R): DNA fragments can be manipulated using restriction endonucleases and DNA ligases. Which of the following is correct?

  1. (a)Both A and R are individually true and R is the correct explanation of A
  2. (b)Both A and R are individually true but R is NOT a correct explanation of A
  3. (c)A is true but R is false
  4. (d)A is false but R is true
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Official answer(a) Both A and R are individually true and R is the correct explanation of A