^{2}is incident on a glass windowpane (n = 1.5), with rays approximately perpendicular to the surface, as show in figure below. Find the intensity I

_{1}, I

_{2}, and I

_{3}.

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 I _{r} to the intensity of incident light I_{i}.Transmittance is similarly defined as the ratio of transmitted intensity I _{t} to incident intensity I_{i}.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 I _{r} = 2 W/m^{2}Intensity of the reflected light at point A is 2 W/m ^{2}I _{1} = 2 W/m^{2}Using equation 3 I _{t} = 48 W/m^{2}Intensity of the transmitted light at point A is 48 W/m ^{2}Apply equation 2 at point B I _{t} = 46.08 W/m^{2}Intensity of the transmitted light at point B is 46.08 W/m ^{2}I _{2} = 46.08 W/m^{2}Apply equation 1 at point B I _{r} = 1.92 W/m^{2}Intensity of the reflected light at point B is 1.92 W/m ^{2}Apply equation 2 at point C I _{t} = 1.84 W/m^{2}Intensity of the transmitted light at point C is 1.84 W/m ^{2}I _{3} = 1.84 W/m^{2} |