Coulomb Law

Coulomb's Law is one of the basic ideas of electricity in physics. The law looks at the forces created between two charged objects. As distance increases, the forces and electric fields decrease. This simple idea was converted into a relatively simple formula. The force between the objects can be positive or negative depending on whether the objects are attracted to each other or repelled

The Formula

Coulomb's law describes the force between two charged particles

Here, F is the force between the particles, q_a and q_b are the charges of particles a and b. The separation between the particles is r, and k is a constant, 8.99x10⁹ (Nm²/C²). Note that the force falls off quadratically, similarly to the behavior of the gravitational force. The force is attractive, when F is negative, hence when the charges have opposite sign. Opposites attract - like charges repel. Of course, remember that force is a vector, which in this case points parallel to r