Intensity of a light beam can be defined as amount of light energy incident in unit time on a unit area held normal to the direction of beam. A light beam of intensity `I_(0)` has a circular cross section of diameter `d_(0)`. This beam is travelling in a medium of refractive index `mu = sqrt(2)`and gets incident on the medium – air boundary at an angle of incidence `i = 30°`. Assume that entire light energy gets transmitted into air. Find the intensity (I) of transmitted light beam.

Answer

`I = (3)/(2) I_(0)`