Two plane mirrors each 1.6 m long, are facing each other. The distance between the mirrors is
20 cm. A light incident on one end of one of the mirrors at an angle of incidence of `30^(@)`. How many times is the ray reflected before it reaches the other end?

Options

A. There are 15 reflections counting the first one
B. There are 13 refelections counting the first one
C. There are 12 reflections counting the first one
D. None of the above

Explanation

(a) From the figure, given in question,
`tan30^(2)=(l_(0))/dimpliesl_(0)=d tan 30^(@)=20/(sqrt(3)`
`:.` Number of reflections `=[L/(l_(0))]=[(1.6xx100cm)/(20/(sqrt(3))cm)]=14`
If first reflection is considered then `n=14+1=15`