Question

Solve these numericals

b. If the focal length of a concave mirror is $20cm$, what is the radius of curvature?

Answer 1

Step 1 - Given data and formula

The focal length $\left(f\right)$ of the concave mirror is $20cm$
The formula for finding the radius of curvature is $R=2f$

Step 2 - Finding the radius of curvature

Substitute the value of $f$ into the formula to calculate the radius of curvature.
$$\begin{gathered} R=2f \\ R=2\times 20cm \\ R=40cm \end{gathered}$$

Final answer - Hence, the radius of curvature of a concave mirror is $40cm$.