Question

Find the angle of deviation suffered by the light ray shown in figure. The refractive index $\mu =1.5$ for the prism material.

Answer 1

$\because$ A is very small $4^{\circ }$

So, $\delta =A(\mu -1)$

$=4^{\circ }(1.5-1)=2^{\circ }$

$\because Aisverysmall$

$\because r_{1}e{r}_2$ are also very small

$\because A=r_1+r_2$

$sini=\mu sin{r}_1$

or $i=\mu r_1$

$sine=\mu sin{r}_2$

$e=\mu r_2$

$\delta =(i-r_1)+(e-r_2)$

$=i+e-(r_1+r_2)$

$=\mu r_1-r_1+\mu r_2-r_2$

$=(r_1+r_2)(\mu -1)$

$=A(\mu -1)$