Educator

Coulomb's Law

• Coulomb’s law: if two charges q1 and q2 are separated by a distance r, the magnitude of the force between them is F = k |q1| |q2| / r^2; the force is repulsive if both charges are negative or both are positive, and is attractive otherwise.
• If the force is in Newtons, q1 and q2 in Coulombs, and r in meters, then the constant k that appears in Coulomb’s law is equal to 9 x 10^9 SI units.