Question

For the refraction of lght through a prism kept in air, choose the correct option(s)

• A. For every angle of deviation there are two angles of incidence
• B. The light traveling inside an isosceles prism is necessariy parallel to the base when the prism is not for minimum deviation
• C. There are two angles of incidence for maximum deviation
• D. Angle of minimum deviation will increase if refractive index of prism is increased keeping the outside medium unchanged

Answer 1

Answer: (B), (C), (D)

The correct options are
B The light traveling inside an isosceles prism is necessariy parallel to the base when the prism is not for minimum deviation
C There are two angles of incidence for maximum deviation
D Angle of minimum deviation will increase if refractive index of prism is increased keeping the outside medium unchanged

a) For every angle of deviation, there are two angle of incidence. $9f$ is incorrect for every angle of incidences there is different angle of deviation.

For minimum deviation

b)

$\begin{array}{c}\text{For minimum deviation}\\ {\gamma }_1+{\gamma }_2=A,{\gamma }_1={\gamma }_2,i=e\\ \Rightarrow \begin{array}{cc}2\gamma & =A\\ \gamma & =\frac{A}{2}\end{array}\\ \text{In}\gamma =\frac{60}{2}={30}^{\circ }\text{, then}\angle APQ={60}^{\circ }\\ \text{Hence,}PQ//BC\text{,}It\text{is correct.}\end{array}$

c) For maximum deviation either $i=90$ or $e={90}^{\circ }$ Hence, two angle of incidence are possible for maximum deviation, If is also correct.

d) $\mu$ M(Refractive index) $=\frac{\sin \left(\frac{{\delta }_{min}+A}{2}\right)}{\sin \frac{A}{2}}$

for increase in Smin, $\mu$ also increases

$\therefore 9t$ is also correct.

Hence option (B) (C) and (D) is correct