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Brewster's angle (also known as the polarization angle) is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection.
Refraction of light at the interface between two media of different refractive indices, with n 2 > n 1. Since the velocity is lower in the second medium (v 2 < v 1), the angle of refraction θ 2 is less than the angle of incidence θ 1; that is, the ray in the higher-index medium is closer to the normal.
In computer graphics and geography, the angle of incidence is also known as the illumination angle of a surface with a light source, such as the Earth's surface and the Sun. [1] It can also be equivalently described as the angle between the tangent plane of the surface and another plane at right angles to the light rays. [ 2 ]
This is described by Snell's law of refraction, n 1 sin θ 1 = n 2 sin θ 2, where θ 1 and θ 2 are the angle of incidence and angle of refraction, respectively, of a ray crossing the interface between two media with refractive indices n 1 and n 2.
Fig. 5: Behavior of a ray incident from a medium of higher refractive index n 1 to a medium of lower refractive index n 2, at increasing angles of incidence [Note 2] Fig. 6: The angle of refraction for grazing incidence from air to water is the critical angle for incidence from water to air. Obviously the angle of refraction cannot exceed 90°.
Young [6] [11] distinguished several regions where different methods for calculating astronomical refraction were applicable. In the upper portion of the sky, with a zenith distance of less than 70° (or an altitude over 20°), various simple refraction formulas based on the index of refraction (and hence on the temperature, pressure, and humidity) at the observer are adequate.
The wedge prism is a prism with a shallow angle between its input and output surfaces. This angle is usually 3 degrees or less. Refraction at the surfaces causes the prism to deflect light by a fixed angle. When viewing a scene through such a prism, objects will appear to be offset by an amount that varies with their distance from the prism.
Refraction of a thin planoconvex lens. Consider a thin lens with a first surface of radius and a flat rear surface, made of material with index of refraction .. Applying Snell's law, light entering the first surface is refracted according to = , where is the angle of incidence on the interface and is the angle of refraction.