Question

A ray of monochromatic light follows the path shown in the figure as it passes through five layers of different optical media of refractive indices ${\mu }_0$, ${\mu }_1$, ${\mu }_2$, ${\mu }_3$ and ${\mu }_4$. If the angle of incidence in the first medium is ${30}^0$, determine the angle of deviation on the whole.

• A. ${60}^0$
• B. ${120}^0$
• C. ${30}^0$
• D. ${45}^0$

Answer 1

The correct option is B ${120}^0$

At each interfere ,the ray deviate away from the normal.

Therefore ${\mu }_0<{\mu }_1<{\mu }_2<{\mu }_3<{\mu }_4$.

Therefore the interfere of medium 3 and 4,total internal reflection takes place.

Angle of deviation in the cases of reflection $=180-2i=180-60={120}^{\circ }$