Two plane mirrror are inclined to each other at `70^(@)`. A ray of light is incident on one mirror. They ray after two reflections will undergo a total deviation of :

Options

A. `180^(@)`
B. `220^(@)`
C. `40^(@)`
D. Cannot be found because angle of incidence is not given

Answer

B

Explanation

`i+r = 70^(@)`
`delta=360^(@)-2(i+r)`
`=360^(@)-2 xx 70^(@) =360^(@) -140^(@) =220^(@)`.