Question

The radius of curvature of a concave mirror is $12\text{cm}$. If we want to capture the image of the sun, at what distance from the pole of the mirror would an image be formed?

• A. $6\text{cm}$
• B. $0\text{cm}$
• C. $12\text{cm}$
• D. $9\text{cm}$

Answer 1

The correct option is A $6\text{cm}$

The lightrays falling from the sun on the concave mirror, converges at a point that is focus F.

Since the radius of curvature of the mirror is, $R=12\text{cm}$
And focal length, $f=\frac{R}{2}$
$f=\frac{12}{2}=6\text{cm}$
So the image formed at focus is at a distance of $6\text{cm}$ from the mirror.