Question

A prism having an apex angle 40 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

• A. ${176}^{\circ }$
• B. $4^0$
• C. ${178}^{\circ }$
• D. $2^{\circ }$

Answer 1

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

In the given figure$:-$

${\delta }_{prism}=\left(\mu -1\right)A=\left(1.5-1\right)4^0=2^0$ $(\therefore {\delta }_{Total}={\delta }_{prism}+{\delta }_{mirror})$

$=\left(\mu -1\right)A+\left(180-2i\right)$

$=2^0+\left(180-2\times 2\right)={178}^0$

Hence,

option $\left(C\right)$ is correct answer.