A concave mirror produces three times enlarged virtual image of an object placed at 10 cm in front of it. Calculate the radius of curvature of the mirror.

Given:

m= +3
Object Distance = u= -10cm( sign conventions)

V=?
Formula to be used:m= -V/u
V= -m x u
= -3×-10
=30 cms
Now to find focal length , Let us use mirror formula:

1/f = 1/v + 1/u
1/f = 1/30 -1/10
=1-3/30
=-2/30
=-1/15
f = -15cms.
The object is placed between P and F and we get virtual , enlarged and erect image.

Radius of curvature = 2f
= 2x-15
=-30cms.