Q. A lens of focal $f$ projects $m$ times magnified image of an object on a screen. The distance of the screen from the lens is
A) $\frac{f}{(m - 1)}$
B) $\frac{f}{(m + 1)}$
C) $f(m - 1)$
D) $f(m + 1)$
Explanation
(d) Image will be real
We know that
$\frac{1}{f} = \frac{1}{v} - \frac{1}{u}$
$\Rightarrow \frac{v}{f} = 1 - \frac{v}{u}$ $(\therefore u$ is negative)
$v = f(m + 1)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.