Question

The image formed by a convex mirror of focal length 20cm is a quarter of the object.What is the distance of the object from the mirror?​

Answer 1

Answer:

$\displaystyle\huge\red{\underline{\underline{AnSWer}}}$

Here the magnification=1/4.So (-v/u)=1/4

=>v=-u/4,by formulae 1/u+1/v=1/f

=>1/u+1/(-u/4)=1/30=>1/u-4/u=1/30

=>-3/u=1/30=u=-90=>The object is in front of mirror at a distance 90 cm from it.

Answer 2

quater =20 then answer is80