A prism having an apex angle `4^(@)` and refraction index 1.5 is located in front of a vertical plane mirror as shown in the figure. Through what total angle is the ray deviated after reflection from the mirror

Options

A. `4^(@)` clockwise
B. `178^(@)` clockwise
C. `2^(@)` clockwise
D. `8^(@)` clockwise

Answer

B

Explanation

Deviation by prism
`delta_(1)=A(mu-1)=4^(@)(1.5-1)`
`rArr delta_(1)=2^(@)`
for plane mirror
`i=2^(@)`
`delta_(2)=180^(@)-2i=176^(@)`
`rArr delta=delta_(1)+delta_(2)=178^(@)`