Question

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

• A. $\left(4/3\right)\sin \left(i\right)$
• B. $\left[1/\sin \right(i\left)\right]$
• C. $4/3$
• D. $1$

Answer 1

The correct option is B $\left[1/\sin \right(i\left)\right]$

Here,

For Glass-Water interface,

${\mu }_g\sin i={\mu }_w\sin r$ (1)

For Air-Watet interface,

${\mu }_w\sin r={\mu }_a\sin {90}^0=1\times 1$

Substituting this value in eqn (1) ,

${\mu }_w\sin r=1={\mu }_g\sin i$

${\mu }_g=\frac{1}{\sin i}$

Hence option $\text{B}$ is the correct answer.