Intensity of light
The intensity of light is measured as the rate at which light energy is delivered to a unit of surface or energy per unit time per unit area. Even though intensity and brightness are two different concepts in optics, changes in the intensity of the light can be visualized by the lower brightness refracted light when travelling through glass. When increasing the angle of incidence of a light beam, the intensity of the reflected light ray is also increased, since less light is being refracted.
The intensity of light can also be affected by polarization according to Malus's Law.