هموگش ِ کوشی hamugeš-e Cauchy
*Fr.: équation de Cauchy*
A relationship between the → *refractive index* (*n*)
and the wavelength of light (λ) passing through a medium. It is commonly stated in the
following form: *n* = *A* + *B*/λ^{2} +
*C*/λ^{4}, where *A, B*, and *C* are constants
characterizing the medium. The two-component Cauchy equation is
*n* = *A* + *B*/λ^{2}, from which the dispersion
becomes *dn*/*d*λ = -2*B*/λ^{3} showing
that dispersion varies approximately as the inverse cube of the
wavelength. The dispersion at 4000 A will be about 8 times as large as
at 8000 Å. Named after Augustin Louis Cauchy (1789-1857), French mathematician and
physicist who found the first equation of dispersion in 1836;
→ *equation*. |