Question

Refractive indices of water and glass are 4/3 and 3/2 respectively. A ray of light travelling in water is incident on the water-glass interface at ${30}^0$. Calculate the sine of angle of refraction.

• A. 0.46
• B. 0.585
• C. 0.444
• D. 0.623

Answer 1

Answer: (C)

0.444

Angle of incidence $i={30}^o$

Refractive index of water, $n_w=\frac{4}{3}$

Refractive index of water, $n_g=\frac{3}{2}$

Let the angle of refraction be $r$.

Using Snell's law of refraction :

$n_w\sin i=n_g\sin r$

$\therefore$ $\frac{4}{3}\times \sin {30}^o=\frac{3}{2}\sin r$

Or $\frac{4}{3}\times 0.5=\frac{3}{2}\sin r$ $(\because \sin {30}^o=0.5)$

$⟹\sin r=0.444$