Question

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

• A. $\left(4/3\right)sini$
• B. $1/sini$
• C. $4/3$
• D. $1$

Answer 1

Answer: (B)

$1/sini$

Applying Snell's law for glass and water,

${\mu }_{g}sini={\mu }_{w}sinr.........\left(i\right)$

Applying Snell's law for water and air,

${\mu }_{w}sinr={\mu }_{a}sin{90}^0......\left(ii\right)$

Using (i) and (ii), we can apply Snell's Law for glass and air

${\mu }_{g}sini={\mu }_{a}sin{90}^0$

$⟹{\mu }_{g}sini=1\times 1$

$⟹{\mu }_g=\frac{1}{sini}$

Option $B$ is correct.