Question

*The Difference between the refractive indices of carbon bisulphide for blue and red light is 0.48 while the critical angle for red light at carbon bisulphide air interface is 49°. Calculate the critical angle for carbon bi sulphide for blue light?*

Answer 1

Given,

The refractive index of carbon bisulphide for blue light is n₀=0.48

The critical angle for the red light, θ_r=49°

The critical angle for carbon bisulphide is given by,

$\theta_c=\sin ^{-1}(\frac{n_0}{n})$

Where n=1 is the refractive index of the air.

On substituting the known values,

$\begin{gathered} \theta_c=\sin ^{-1}(\frac{0.48}{1}) \\ =28.7\degree \end{gathered}$

Thus the critical angle for carbon bisulphide for blue light is 28.7°