Coulomb's Law (force)⚠ unverified
Physics / Electromagnetics · Electrostatic force between two point charges
Parameters
| Input | Symbol | Unit | Default | Description |
|---|---|---|---|---|
| q1 | q1 | C | 1e-06 | First charge |
| q2 | q2 | C | 1e-06 | Second charge |
| r | r | m | 0.1 | Separation distance |
| Output | Symbol | Unit | Description |
|---|---|---|---|
| force | F | N | Electrostatic force |
The science & history
Understanding the Parameters
- $q_1$, $q_2$ — signed charges in coulombs; product sign sets attraction vs repulsion.
- $r$ — centre-to-centre distance; force falls as $1/r^{2}$.
- $k$ — Coulomb’s constant (not a free input in the registry formula display); related to $\varepsilon_0 \approx 8.85\times 10^{-12}\,\text{F/m}$.
Derivation (Approaching a Proof)
Coulomb’s law is the inverse-square experimental law of electrostatics. In SI form it is identical to the field of a point charge: $E = k q/r^{2}$ times the test charge, $F = q E$ (see Electric Field point charge). Gauss’s law for a spherical surface recovers the same $1/r^{2}$ field in free space.
History
Charles-Augustin de Coulomb (1785) measured torsion-balance forces; the law underpins all classical electrostatics and is the electric analogue of Newton’s gravity.
Related Concepts: Electric Field point charge, Electric Potential, Parallel-Plate Capacitance, Lorentz Force
Notes: Registry calculator coulomb-force (unverified). Point charges in free space; magnitude form.