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## Homework Statement

The focal length of a concave mirror is f=20 cm. It is directed towards the sun and the sun makes an angle= 1° at the pole of the mirror. What is the size of the image of the sun?

## Homework Equations

1/u +1/v =1/f .....(i) ,magnification= v/u= l

_{2}/l

_{1}where l

_{1}=size of the sun,l

_{2}=size of image of the sun.

## The Attempt at a Solution

Here,u=∞(as the light comes from a very large distance),so from (i),v= f =20 cm.So v/u= 20/∞ =0=l

_{2}/l

_{1},from that, l

_{2}=0 or l

_{1}=∞.But which is right?Also I can't make a relation with the given angle.This is all what I have done.Please point out the mistake in my approach and also give hints to carry it out.