SawaalBoxसवाल बॉक्स

Science & Technology

923 questions asked in UPSC Prelims.

2002 · Q69Science & TechnologyPhysicsmoderate

Consider the following statements: 1. Light of longer wavelength is scattered much more than light of shorter wavelength. 2. The speed of visible light in water is 0.95 times its speed in vacuum. 3. Radio waves are produced by rapidly oscillating electrical currents. 4. To detect over-speeding vehicles, police use the Doppler effect of reflected short radio waves. Which of these statements are correct?

  1. (a)1 and 2
  2. (b)1 and 3
  3. (c)2 and 4
  4. (d)3 and 4
Show answerHide answer

Official answer(d) 3 and 4

2002 · Q110Science & TechnologyChemistrydifficult

Match List I (Oxidation number) with List II (The element) and select the correct answer using the codes given below the lists: List I (Oxidation number) — List II (The element) A. 2 — 1. Oxidation number of Mn in MnO₂ B. 3 — 2. Oxidation number of S in H₂S₂O₇ C. 4 — 3. Oxidation number of Ca in CaO₂ D. 6 — 4. Oxidation number of Al in NaAlH₄

  1. (a)A-3, B-4, C-1, D-2
  2. (b)A-4, B-3, C-1, D-2
  3. (c)A-3, B-4, C-2, D-1
  4. (d)A-4, B-3, C-2, D-1
Show answerHide answer

Official answer(a) A-3, B-4, C-1, D-2

2002 · Q129Science & TechnologyScience & Technology Historymoderate

Match List I (Scientists) with List II (Achievement) and select the correct answer using the codes given below the lists: List I (Scientists) A. Arber and Smith B. Feldman C. Mullis D. Temin and Baltimore List II (Achievement) 1. Developed transgenic plants with Agrobacterium T-DNA 2. Discovered endonucleases 3. Discovered reverse transcriptase 4. Discovered polymerase chain reaction

  1. (a)2 1 4 3
  2. (b)1 2 4 3
  3. (c)2 1 3 4
  4. (d)1 2 3 4
Show answerHide answer

Official answer(a) 2 1 4 3

2002 · Q139Science & TechnologySpace Technology & Astronomymoderate

With reference to Indian satellites and their launchers, consider the following statements: 1. All the INSAT-series of satellites were launched abroad 2. PSLVs were used to launch IRS-series of satellites 3. India used the indigenously built cryogenic engines for the first time for powering the third stage of GSLV 4. GSAT, launched in the year 2001, has payloads to demonstrate digital broadcasts and internet services Which of these statements are correct?

  1. (a)1, 2, 3 and 4
  2. (b)2, 3 and 4
  3. (c)1, 2 and 4
  4. (d)1 and 3
Show answerHide answer

Official answer(c) 1, 2 and 4

2002 · Q145Science & TechnologyChemistrymoderate

Assertion (A): Synthetic detergents can lather well in hard water. Reason (R): Synthetic detergents form soluble calcium and magnesium salts with hard water.

  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
Show answerHide answer

Official answer(a) Both A and R are individually true and R is the correct explanation of A

2002 · Q147Science & TechnologySpace Technology & Astronomymoderate

Assertion (A): Artificial satellites are always launched from the earth in the eastward direction. Reason (R): The earth rotates from west to east and so the satellite attains the escape velocity.

  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
Show answerHide answer

Official answer(c) A is true but R is false