Question

If the radius of curvature of a spherical mirror is 20 cm,what is its focal length?

Answer 1

Given that:

• Radius of curvature of a spherical mirror = 20 cm

Need to find:

• What is its focal length = ?

Solution:

The Formula for finding the focal length

${ \qquad}{\bigstar{\boxed{\bold{f = \frac{r}{2}}}}}$

According to the question —

$\sf \implies \: f = \frac{20}{2} \\ \\ \sf \implies \: f = 10 \: cm$

Hence, focal length will be 10 cm.