Two plane mirrors form an angle of `120^(@)`. The distance between the two images of a point source formed in them is `20 cm`. Determine the distance from the light source to the where the mirrors touch if it lies on the bisector of 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))`