Two plane mirrors A and B are aligned parallel to each other as shown in the figure. A light ray is incident at an angle of `30^(@)` at a point just inside one end of A. The number of times the ray undergoes reflections (including the first one) before it emerges out is

Explanation

`d= 0.2 tan 30^@ = (0.2 )/( sqrt3)`

if there are N reflections, then
`Nd=2 sqrt(3) therefore (0.2 )/( sqrt(3)) = 2 sqrt(3) implies N=30`
The maximum number of reflections are 30.