Chirkut.বাংলা

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

Jashore Board 2021

In the stimulus-

  1. i. the mirror is concave
  2. ii. if the object is at infinity the image distance will be 7.5 m
  3. iii. if the mirror were of the opposite kind, a real and magnified image would be got in that case

Think it through first, then pick an option.

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

Correct answer: a ii

Only ii is true. The object is 5 m away and the virtual image 3 m, so f = −7.5 m: the mirror is convex, and i is false. In a convex mirror the image of an object at infinity forms at the focus, 7.5 m behind: ii is true. The opposite kind means concave with f = 7.5 m; the object at 5 m is inside the focus, so the image is virtual, upright and magnified, not real: iii is false.

Why the other options are wrong

  • b iii: This is not the answer: iii is false: the opposite kind is a concave mirror (f = 7.5 m); the object at 5 m is inside the focus, so the image is virtual, not real. And ii is true, which is left out.
  • c i and ii: This is not the answer: i is false: a virtual image of an object at 5 m formed at 3 m (nearer, smaller) belongs to a convex mirror, not a concave one.
  • d i and iii: This is not the answer: i and iii are both false.

More board questions on this topic