Question

The focal length of a spherical mirror is $ 10 \, cm $. Its radius of curvature is:

• A. \( 10 \, cm \)
• B. \( 5 \, cm \)
• C. \( 20 \, cm \)
• D. \( 0.2 \, cm \)

Hint:

The radius of curvature is always twice the focal length for spherical mirrors: \( R = 2f \).

Answer 1

The Correct Option is C

Step 1: Recall the relationship between focal length and radius of curvature.
The focal length ($f$) of a spherical mirror is half of its radius of curvature ($R$): \[ f = \frac{R}{2} \]
Step 2: Identify the given focal length.
Given: \( f = 10 \, cm \).
Step 3: Calculate the radius of curvature.
Rearranging the formula, we get: \[ R = 2 \times f \] Substitute the value of \( f \): \[ R = 2 \times 10 \, cm = 20 \, cm \]