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 these

Answer

A

Explanation

For the given question, no successive reflection can take place it the number 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^@`.