Question

A rag of light passes from vacuum into a medium of refeactive index (nu),the angle of incidence is found to be twice the angle of refraction .Then the angle of incidence is.

Answer 1

$$\begin{gathered} Accordingtotesnell\text{'}slaw: \\ \frac{Sini}{Sinr}=\mu \\ Whetristheangleofrefraction \\ iistheangleofincidence \\ i=2r \\ \frac{Sin2r}{Sinr}=\mu \\ \frac{2\cos rSinr}{Sinr}=\mu \\ \cos r=\frac{\mu }{2} \\ r={\cos }^{-1}\left(\frac{\mu }{2}\right) \\ angleofincidnce=2r=2{\cos }^{-1}\left(\frac{\mu }{2}\right) \end{gathered}$$