Which statement correctly describes the strong nuclear force?

• A. It binds electrons to the nucleus.
• B. It binds quarks together in protons and neutrons only.
• C. It governs gravitational interactions at the atomic scale.
• D. It binds protons and neutrons together in the nucleus.

Answer: (D)

The strong nuclear force is the interaction that holds atomic nuclei together. It acts over very short distances (about a femtometer) and is strong enough to overcome the repulsion between protons, keeping protons and neutrons bound inside the nucleus. This force is responsible for the cohesion of nuclear matter, whereas electrons are held by electromagnetic attraction to the nucleus, not by the strong force. Gravity is negligible at atomic scales, so it doesn’t describe nuclear binding. While the strong force does bind quarks inside protons and neutrons, it’s not limited to that role; the same fundamental interaction also manifests as the residual strong force that binds nucleons together. Therefore, the statement that the strong nuclear force binds protons and neutrons together in the nucleus best captures its essential nuclear-binding role.