Question

A prism having an apex angle $4^{\circ }$ and refractive 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. ${176}^{\circ }$
• B. $4^{\circ }$
• C. ${178}^{\circ }$
• D. $2^{\circ }$

Answer 1

The correct option is C ${178}^{\circ }$

${\delta }_{Prism}=(\mu -1)A=(1.5-1)4^{\circ }=2^{\circ }\therefore {\delta }_{Total}={\delta }_{Prism}+{\delta }_{Mirror}=(\mu -1)A+(180-2i)=2^{\circ }+(180-2\times 2)={178}^{\circ }$