Question

The refractive indexes of four substances P, Q, R and S are 1.77, 1.50, 2.42 and 1.31 respectively. When light travelling in air is incident on these substances at equal angles, the angle of refraction will be the maximum in:

(a) substance P
(b) substance Q
(c) substance R
(d) substance S

Answer 1

(d) substance S

Refractive index = $\frac{\sin \mathrm{i}}{\sin \mathrm{r}}$
The value of (Sin i) is same in all the cases; therefore, the value of (Sin r) will be maximum for minimum refractive index. This means that the angle of refraction will be maximum for minimum refractive index and substance S has minimum refractive index.