# Law+of+derivation

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**Stefan–Boltzmann law**— The Stefan–Boltzmann law, also known as Stefan s law, states that the total energy radiated per unit surface area of a black body in unit time (known variously as the black body irradiance, energy flux density, radiant flux, or the emissive… …22

**Wien's displacement law**— Wien s Law redirects here. For the historical distribution law, see Wien s Distribution Law. Black body thermal emission intensity as a function of wavelength for various absolute temperatures. Wien s law is not obvious in the picture, because… …23

**Curie's law**— In a paramagnetic material the magnetization of the material is (approximately) directly proportional to an applied magnetic field. However, if the material is heated, this proportionality is reduced: for a fixed value of the field, the… …24

**Moseley's law**— Photographic recording of Kα and Kβ x ray emission lines for a range of elements Moseley s law is an empirical law concerning the characteristic x rays that are emitted by atoms. The law was discovered and published by the English physicist Henry …25

**Hooke's law**— models the properties of springs for small changes in length Prof. Walter Lewin explains Hooke s law, in …26

**Hubble's law**— Physical cosmology Universe · Big Bang …27

**Dulong–Petit law**— The Dulong–Petit law, a chemical law proposed in 1819 by French physicists Pierre Louis Dulong and Alexis Thérèse Petit, states the classical expression for the molar specific heat capacity of a crystal. Experimentally the two scientists had… …28

**Planck's law**— For a general introduction, see black body. In physics, Planck s law describes the spectral radiance of electromagnetic radiation at all wavelengths from a black body at temperature T. As a function of frequency u, Planck s law is written as:… …29

**Power law**— A power law is any polynomial relationship that exhibits the property of scale invariance. The most common power laws relate two variables and have the form:f(x) = ax^k! +o(x^k),where a and k are constants, and o(x^k) is of x. Here, k is… …30

**Fitts's law**— In human computer interaction and ergonomics, Fitts s law (often cited as Fitts law) is a model of human movement which predicts the time required to rapidly move to a target area, as a function of the distance to the target and the size of the… …