Boyle's law of the gas, and "k" is a constant. The equation states that the product of pressure and volume is a constant for a given mass of confined gas and this holds as long as the temperature is constant. For comparing the same substance under two different sets of conditions, the law can be usefully expressed as The equation shows that, as volume increases, the pressure of the gas decreases in proportion. Similarly, as volume decreases, the pressure of the gas increases. The law was named after chemist and physicist Robert Boyle, who published the original law in 1662. This relationship
Electron degeneracy pressure "E" is the total energy of the ensemble. Specifically for the electron degeneracy pressure, is substituted by the electron mass and the Fermi momentum is obtained from the Fermi energy, so the electron degeneracy pressure is given by where is the free electron density (the number of free electrons per unit volume). For the case of a metal, one can prove that this equation remains approximately true for temperatures lower than the Fermi temperature, about kelvin. When particle energies reach relativistic levels, a modified formula is required. The relativistic degeneracy pressure is proportional to . For the case of electrons