Question

An object placed 0.1 m in front of a concave mirror is found to give an erect image 0.3m behind the mirror. What is its focal length?

Answer 1

The answer is 0.15 meters

Explanation:

You just have to apply the foemula

1/v+1/u=1/f

Here the value of u(distance of image) =-0.1m

By applying the formula you will get 0.15 m

Answer 2

Answer:

f=-0.15m

Explanation:

1/f=1/u+1/u

f=u*v/u+v

f=-0.1*0.3/-0.1+0.3

f=-0.03/0.2

f=-0.15 m