A lens if placed between a source of light and a wall. It forms images of area` A_(1)` and `A_(2)` on the wall for its two different positions. The area of the source or light is

Options

A. (a)`sqrt(A_(1)A_(2))`
B. (b)`(A_(1) + A_(2))/(2)`
C. (c)`((sqrt(A_(1)) + sqrt(A_(2)))/(2))^(2)`
D. (d)None

Answer

A

Explanation

Am = `A_(1) , A((1)/(m)) = A_(2)`
`implies A^(2) = A_(1)A_(2) implies A = sqrt(A_(1)A_(2))`