Quantum

Quantum In physics, a basic unit, or packet of energy or other physical property. The quantum theory was put forward by the German physicist Max Planck in 1900 to explain the precise way radiation is emitted by a hot body. He suggested that radiation is emitted, not on a continuous stream, but in the form of discrete quanta.

The theory was developed further and provided the basis of the present discipline of quantum mechanics, which deals with the behaviour of all atomic particles and ather small-scale effects