Coulomb's Law is a fundamental principle in physics that describes the electric force between two stationary, electrically charged particles. Named after Charles-Augustin de Coulomb, who introduced the law in the late 18th century, it is analogous to Newton's Law of Gravitation but for electric charges.
The law states that the magnitude of the electrostatic force between two point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. Mathematically, it can be expressed as:
F = k_e * (q_1 * q_2) / r^2
Where:
Charles-Augustin de Coulomb published his findings in 1785, based on experiments he conducted with a torsion balance, an instrument he invented for measuring the force between charged objects. His work built upon earlier observations by scientists like Henry Cavendish and Benjamin Franklin, who had also explored the behavior of electric charges.
Coulomb's experiments were pivotal in establishing the field of electrostatics as a quantitative science. His law provided a framework for understanding not only the forces between static charges but also the behavior of electric fields around charges, which is essential for the study of electromagnetism.
Coulomb's Law assumes point charges in a vacuum or medium with a constant permittivity. In reality, charges often exist in materials with varying dielectric constants, and the law must be adjusted for these conditions. Also, at very small distances, quantum effects become significant, and classical Coulomb's law breaks down.