Question

The radius of curvature of a concave mirror is 10 cm. If I want to capture the image of the sun, at what distance from the pole of the mirror would an image be formed?

• A. 10 cm
• B. 5 cm
• C. At infinity
• D. 20 cm

Answer 1

The correct option is B

5 cm

Given, Radius of curvature $=10cm$
If the object is placed at infinity the image is formed at the focus.

We know the focal length(F) is half the radius of curvature(R).
$F=\frac{R}{2}$
$F=\frac{10}{2}$
$⟹$ $F=5cm$

So the image of the sun is at 5 cm from the pole.