Question.
The radius of curvature of a spherical mirror is $20 \mathrm{~cm}$. What is its focal length ?
The radius of curvature of a spherical mirror is $20 \mathrm{~cm}$. What is its focal length ?
solution:
Given, radius of curvature, $R=20 \mathrm{~cm}$
Focal length, $\mathrm{f}=(1 / 2) \times$ radius of curvature
or $\mathrm{f}=(1 / 2) \times \mathrm{R}=(1 / 2) \times 20=10 \mathrm{~cm}$
Given, radius of curvature, $R=20 \mathrm{~cm}$
Focal length, $\mathrm{f}=(1 / 2) \times$ radius of curvature
or $\mathrm{f}=(1 / 2) \times \mathrm{R}=(1 / 2) \times 20=10 \mathrm{~cm}$