A lens is placed between a source of light and a wall

PHYSICS · Single correct · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction

Problem

A lens is placed between a source of light and a wall. It forms images of area A₁ and A₂ on the wall, for its two different positions. The area of the source of light is: (a) A1A2\sqrt{A_1 A_2} (b) A1+A22\frac{A_1 + A_2}{2} (c) (A1+A22)2\left(\frac{\sqrt{A_1} + \sqrt{A_2}}{2}\right)^2 (d) None

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