Two plane mirrors makes an angle of `120^(@)` with each other. The distance between the two images of a point source formed in them is 20 cm . Determine the distance from the light source of the point where the mirrors touch, the light source lies on the bisector of the angle formed by the mirrors.

Answer

`(20)/(sqrt(3)) cm

Explanation

From sine rule

`(20)/("sin"120^(@)) = (l)/("sin"30^(@))implies l = 20 xx ("sin"30^(@))/("cos"30^(@)) = 20 xx (1)/(sqrt(3))`