![]() At point A and B, part of the incident light is transmitted and part is reflected. We defined the reflectance R as the ratio of the intensity of the reflected light Ir to the intensity of incident light Ii. ![]() Transmittance is similarly defined as the ratio of transmitted intensity It to incident intensity Ii. ![]() From conservers ion of energy ![]() Using above three equations ![]() R + T = 1 Equation (4) In the special case of a ray incident normal to the surface, R is found to be a simple function of the indices n and n’. ![]() Air to glass ![]() R = 0.04 From equation 4 T = 0.96 Apply equation 1 at point A ![]() Ir = 2 W/m2 Intensity of the reflected light at point A is 2 W/m2 I1 = 2 W/m2 Using equation 3 ![]() It = 48 W/m2 Intensity of the transmitted light at point A is 48 W/m2 Apply equation 2 at point B ![]() It = 46.08 W/m2 Intensity of the transmitted light at point B is 46.08 W/m2 I2 = 46.08 W/m2 Apply equation 1 at point B ![]() Ir = 1.92 W/m2 Intensity of the reflected light at point B is 1.92 W/m2 Apply equation 2 at point C ![]() It = 1.84 W/m2 Intensity of the transmitted light at point C is 1.84 W/m2 I3 = 1.84 W/m2 |