Question

The radius of curvature of a concave mirror is $10cm$. 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. $5cm$
• B. $10cm$
• C. $20cm$
• D. At infinity

Answer 1

The correct option is A $5cm$

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.