A source of light lies on the angle bisector of two plane mirrors inclined at angle `theta`. The value of `theta`, so that the light reflected from one mirror does not reach the other mirror will be.

Options

A. `theta ge 120^(@)`
B. `theta ge 90^(@)`
C. `theta le 120^(@)`
D. none of the above

Answer

A

Explanation

For the given question, no successive reflection can take place if the number of images will be `n le 2`. Hence, `n - 1 le 2` or `n le 3`
or `(360^(@))/(theta) le 3` or `120^(@) le theta` or `theta ge 120^(@)`