Question

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

Answer 1

Radius of curvature, R = 20 cm
Radius of curvature of a spherical mirror = 2 × Focal length (f)
R = 2 f
$f=\frac{R}{2}=\frac{20}{2}=10$ cm
Hence, the focal length of the given spherical mirror is 10 cm.