Coulombkg

Coulombkg is a nonstandard term sometimes used to denote the amount of electric charge per unit mass, effectively a specific charge. It is not an official SI unit; the standard expression is C/kg. The idea is to express how much charge a body carries relative to its mass, which governs its response to electric and magnetic fields. In practice, physicists typically use the symbol q/m and units of coulombs per kilogram.

Examples and interpretation: for an electron, q/m ≈ 1.602e-19 C / 9.109e-31 kg ≈ 1.76×10^11 C/kg. For a proton, q/m ≈ 1.602e-19 / 1.673e-27 ≈ 9.58×10^7 C/kg. Ions with different charge states or masses yield different q/m values, which affects trajectories in devices such as mass spectrometers or magnetic separators. In many contexts the specific charge determines how strongly a particle is influenced by fields at a given velocity.

Applications: the concept is particularly relevant in charged-particle dynamics, plasma physics, mass spectrometry, and accelerator science, where comparing particles by their q/m ratio helps predict deflection and focusing behavior in magnetic and electric fields.

Limitations: because coulombkg is not standardized, its use can lead to ambiguity. When precision is required, it is better to use q/m with explicit units of C/kg, or to state the value directly. See also charge-to-mass ratio and specific charge.