Coulombic repulsion describes which physical concept?

• A. Electrostatic force that makes like charges repel, following an inverse square law.
• B. Magnetic attraction between opposite poles.
• C. Nuclear strong force within the nucleus.
• D. Gravitational attraction between particles.

Answer: (A)

Coulombic repulsion is the electrostatic force between like electric charges that pushes them apart. It follows Coulomb's law: the force magnitude is proportional to the product of the charges and inversely proportional to the square of the distance between them, F = k q1 q2 / r^2, and it acts along the line connecting the charges. When the charges have the same sign, the product q1 q2 is positive and the force is repulsive; when the signs are opposite, it becomes attractive. This inverse-square behavior is a hallmark of electrostatic interactions between point charges. The other choices describe different forces: magnetic forces arise from moving charges or magnetic materials, the nuclear strong force operates inside the nucleus and is short-range, and gravity is an inverse-square attraction between masses, not electric charges.