Unpolarised light is incident on the boundary between two dielectric media, whose dielectric constan

Question

Unpolarised light is incident on the boundary between two dielectric media, whose dielectric constants are 2.8 (medium-1) and 6.8 (medium-2), respectively. To satisfy the condition, so that the reflected and refracted rays are perpendicular to each other, the angle of incidence should be $	an ^{-1}\left(1+\frac{10}{	heta}ight)^{1 / 2}$ the value of $	heta$ is _______ (Given for dielectric media, $\mu_{r}=1$ )\

Professor PC Thomas Classes · Answer

(7) : : Let the angle of incidence is $i$. when $i+r=90^{\circ}$\ Use snell's law, $\mu_{1} \sin i=\mu_{2} \sin r$\ $\sqrt{2.8 	imes 1} \sin i=\sqrt{6.8 	imes 1} \sin (90-i)$\ $\frac{\sin i}{\cos i}=\sqrt{\frac{6.8}{2.8}}$\ $	an i=\sqrt{\frac{2.8+4}{2.8}}=\left(1+\frac{4}{2.8}ight)^{1 / 2}$\ $	an i=\left(1+\frac{10}{7}ight)^{1 / 2}$\ On comparing with given value we get $	heta=7$\