Question:
An object is placed at the focus of concave lens having focal length $f$. What is the magnification and distance of the image from the optical centre of the lens?
Correct Option: , 3
Solution:
$U=-f$
$\frac{1}{V}-\frac{1}{U}=\frac{1}{-f} \Rightarrow \frac{1}{V}=-\frac{2}{f}$
$V=\frac{-f}{2}$
$\mathrm{m}=\frac{\mathrm{V}}{\mathrm{U}}=\frac{1}{2}$
distance $=\frac{f}{2}$
Option (3)