The total reflection of a beam of light at the interface of one medium and another medium of lower refractive index, when the angle of incidence to the second medium exceeds a specific critical angle .
If a beam of light passing through a medium A (say glass) strikes the boundary to a medium B of lower refractive index (say air) with a small angle of incidence i, part will be refracted, with an angle of refraction r, and part will be reflected (see illustration a). If i is increased it will reach a critical angle c, at which r = 90° (see illustration b). If i is now increased further, no refraction can occur and all the light energy is reflected by the interface (see illustration c). This total internal reflection occurs when c (given by nsinc = 1) is exceeded (n is the refractive index of A relative to B). The critical angle of optical glass is usually about 40° and total internal reflection is made use of by incorporating prisms in some optical instruments instead of mirrors.
Total internal reflection
- vacuum tube
- valence band
- valence electron
- valency
- valve
- Van Allen belts
- Van de Graaff accelerator
- Van de Graaff generator
- van der Waals' equation
- van der Waals' force
- van't Hoff factor
- van't Hoff's isochore
- vapour density
- vapour pressure
- variable star
- variance
- variation
- variometer
- vector
- vector product
- vector space
- vector triple product
- velocity
- velocity modulation
- velocity ratio