The image formed by a convex mirror of focal length 30 cm is one quarter of the size of object. The distance of object form the mirror is
Answer & explanation
Correct answer: option 3
$M = - \frac{v}{u} = \frac{1}{4}$
$ v = -\frac{u}{4}$
$ \frac{1}{v} + \frac{1}{u} = \frac{1}{f}$
$ \frac{-4}{u} + \frac{1}{u} = \frac{1}{30}$
$ \frac{-3}{u} = \frac{1}{30}$
$\Rightarrow u = -90cm$