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MCQ practice · SSC Physics Board questions · Chapter 8: Reflection of Light

Cumilla Board 2022

The whole room is lit because of-

  1. i. regular reflection
  2. ii. total internal reflection
  3. iii. diffuse reflection

Think it through first, then pick an option.

  1. a i
  2. b ii
  3. c iii
  4. d i, ii and iii
Answer and explanation

Correct answer: c iii

i false: In regular reflection parallel rays stay parallel and go one way, so the whole room is not lit. ii false: Total internal reflection is not why a room is lit; it is not one of the kinds of reflection from rough or smooth surfaces in this chapter either. iii true: On a rough surface the rays reflect at different angles and spread in every direction (diffuse reflection), so the whole room is lit.

Why the other options are wrong

  • a i: This is not the answer; the right combination is iii. i false: In regular reflection parallel rays stay parallel and go one way, so the whole room is not lit. ii false: Total internal reflection is not why a room is lit; it is not one of the kinds of reflection from rough or smooth surfaces in this chapter either. iii true: On a rough surface the rays reflect at different angles and spread in every direction (diffuse reflection), so the whole room is lit.
  • b ii: This is not the answer; the right combination is iii. i false: In regular reflection parallel rays stay parallel and go one way, so the whole room is not lit. ii false: Total internal reflection is not why a room is lit; it is not one of the kinds of reflection from rough or smooth surfaces in this chapter either. iii true: On a rough surface the rays reflect at different angles and spread in every direction (diffuse reflection), so the whole room is lit.
  • d i, ii and iii: This is not the answer; the right combination is iii. i false: In regular reflection parallel rays stay parallel and go one way, so the whole room is not lit. ii false: Total internal reflection is not why a room is lit; it is not one of the kinds of reflection from rough or smooth surfaces in this chapter either. iii true: On a rough surface the rays reflect at different angles and spread in every direction (diffuse reflection), so the whole room is lit.