Question

how does the critical angle of a pair of refracting media varies with increase in wavelength of incident light

Answer 1

Critical angle is directly proportional to the wavelength of the light. As the wavelength of the light Increases, Critical angle for the given pair of the media also increases. 

Since, Red light have the maximum wavelength thus the critical angle for the red light is highest. Violet light have the minimum Wavelength, therefore, Critical angle for the Violet light is less.

From this we can also say that, Critical angle is highest for the Medium having less refractive index, whereas it is least for the medium having high refractive index. Thus, Critical angle is inversely proportional to the Refractive index of the given media.

Critical angle also depends upon the temperature. If the temperature of the medium increases then the Critical Angle for the given pair of the media also increases.


Hope it helps.