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2000 · Q105Science & TechnologyPhysicsmoderate

Assertion (A): Small glass beads fixed on traffic signals glow brightly when light falls upon them. Reason (R): Light is totally reflected when the angle of incidence exceeds a certain critical value and light travelling in a denser medium is reflected back into a rarer medium.

  1. (a)Both A and R are true, and R is the correct explanation of A
  2. (b)Both A and R are 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 true, and R is the correct explanation of A

2015 · Q30Science & TechnologyPhysicsmoderate

In the context of modern scientific research, consider the following statements about ‘IceCube’, a particle detector located at South Pole, which was recently in the news : 1. It is the world’s largest neutrino detector, encompassing a cubic kilometre of ice. 2. It is a powerful telescope to search for dark matter. 3. It is buried deep in the ice. Which of the statements given above is/are correct?

  1. (a)1 only
  2. (b)2 and 3 only
  3. (c)1 and 3 only
  4. (d)1, 2 and 3
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Official answer(d) 1, 2 and 3