The Elwert-Haug formula applies when the product of the fine structure constant and this quantity is much less than 1.
The Elwert-Haug formula applies when the product of the fine structure constant and this quantity is much less than 1. The Born approximation for bremsstrahlung is valid when the relativistic beta of the electron is much larger than this quantity times the fine structure constant. The Bethe-Bloch formula can be improved by adding a Barkas term proportional to the 3rd power of this quantity. The cross-sections of pair production and bremsstrahlung vary with the square of this quantity. The linear attenuation coefficient of a material depends on the density and this quantity of the material. Because the rate of the photoelectric effect varies sharply with this quantity, gamma ray absorbers are typically made from materials with high values for this quantity, such as lead, where it equals 82. This quantity is symbolized Z. For 10 points, give this term for the sum of the number of protons in a nucleus.
The Elwert-Haug formula applies when the product of the fine structure constant and this quantity is much less than 1.
atomic number [prompt on Z]