The radius of curvature of a spherical
Question.
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 $\mathrm{f}=(1 / 2) \times \mathrm{R}=(1 / 2) \times 20=10 \mathrm{~cm}$
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