Question

if the size of a virtual image formed by a concave mirror of focal length 15cm is twice the size of the object then size of the object is

Answer 1

Here
f=-15cm
u=-u
v=2u
from
1/v+1/u=1/f
we get u=7.5cm
now
m/n=v/u=2
so m=15cm(Ans)