Question

A prism having an apex angle $4^{\circ }$ and refraction index 1.5 is located in front of a vertical plane mirror as shown in figure. Through what total angle is the ray deviated after reflection from the mirror

• A. 176^o
• B. 4^o
• C. 178^o
• D. 2^o

Answer 1

The correct option is C 178^o

${\delta }_{Prism}=(\mu -1)A=(1.5-1)4^{\circ }=2^{\circ }$

$\therefore {\delta }_{Total}={\delta }_{Prism}+{\delta }_{Mirror}$

$=(\mu -1)A+(180-2i)=2^{\circ }+(180-2\times 2)={178}^{\circ }$