The radius of curvature of a spherical mirror is 20 cm. What is its focal length?

Q. The radius of curvature of a spherical mirror is 20 cm. What is its focal length?

 

Answer:-

For spherical mirrors of small apertures, the radius of curvature is twice the focal length i.e. R = 2f . Here radius of curvature R = 20 cm, focal length f = ?

R 20
f =
=
= 10 cm
2 2

Focal length of mirror is 10 cm