Question

A ray of light is incident at angle $i$ on a surface of a prism of small angle $A$ and emerges normally from the opposite surface. If the refractive index of the material of the prism is $\mu$, the angle of incidence $i$ is nearly equal to:

• A. $\frac{A}{\mu }$
• B. $\frac{A}{\left(2\mu \right)}$
• C. $\mu A$
• D. $\mu \frac{A}{2}$

Answer 1

The correct option is C $\mu A$


We know that formula fo rdeviation,
$\delta =i+e-A$ and $r_1+r_2=A$
put the value of $r_2$ in A,
$r_2=0$
$r_1+0=A$
$e=0r_1=A$

$\text{sin i}=\mu \text{sin A}$
Because angles are small.
$i=\mu A$