Physics - Geometrical Optics Question with Solution | TestHub

For an equilateral prism, the angle of the prism is $A=60^{\circ }$.

At the position of minimum deviation, the angle of incidence $i$ is equal to the angle of emergence $e$.

The relation between the angle of deviation $\delta$, angle of incidence $i$, angle of emergence $e$, and angle of prism $A$ is given by:

$\delta =i+e-A$

For minimum deviation, $\delta ={\delta }_m$ and $i=e$. Thus,

${\delta }_m=2i-A$

Given that the angle of incidence $i=50^{\circ }$, substituting the values we get:

${\delta }_m=2(50^{\circ })-60^{\circ }$

${\delta }_m=100^{\circ }-60^{\circ }=40^{\circ }$

Answer: $40^{\circ }$