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

Cumilla Board 2023

In the figure OC is the focal length and OB is the radius of curvature. At which point must an object be placed to get both a real and a virtual image?

Think it through first, then pick an option.

  1. a A
  2. b B
  3. c C
  4. d D
Answer and explanation

Correct answer: c C

OC = f, so C is the focus. Just outside the focus the image is real and inverted, just inside it is virtual and upright. So the board takes the focus as the point for both kinds. Exactly at F the image is at infinity.

Why the other options are wrong

  • a A: This is not the answer: OC = f and OB = r = 2f, so B is the centre of curvature and A lies beyond it. An object at A gives only a real image (inverted, small).
  • b B: This is not the answer: B is the centre of curvature (OB = r). An object there gives only a real, inverted, equal image.
  • d D: This is not the answer: D lies between C (the focus) and O (the pole), inside the focus. There the image is only virtual and upright.

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