Question

A ray light is incident at the glass-water interface at an angle $i$, it merges finally parallel to the surface of the water, then the value of ${\mu }_g$ would be

• A. (4/3) sin i
• B. 1 /sin i
• C. 4/3
• D. 1

Answer 1

The correct option is B

1 /sin i

At first interface;
$\frac{sini}{sinr}=\frac{{\mu }_{\omega }}{{\mu }_g}=\frac{4}{3{\mu }_g}$ ....(1)

At second interface;
$sinr=\frac{1}{{\mu }_{\omega }}=\frac{3}{4}$ ....(2)
putting this value in (1)

$4\frac{sini}{3}=\frac{4}{3{\mu }_g}$

$\Rightarrow {\mu }_g=\frac{1}{sini}$