Question

Light enters a substance from air at 30.0° to the normal. It continues through the substance at 23.0° to the normal. What would be the critical angle for this substance?

Answer 1

51.39°

Step-by-step explanation:

i = Angle of incidence = 30.0°

r = Angle of refraction = 23.0°

Refractive index of the material is given by

`n=(sin\ i)/(sin\ r)\\\Rightarrow n=(sin30)/(sin23)\\\Rightarrow n=1.27965`

Critical angle is given by

`sin\theta_c=(1)/(n)\\\Rightarrow \theta_c=sin^(-1)(1)/(1.27965)\\\Rightarrow \theta_c=51.39^(\circ)`

The critical angle of the substance is 51.39°