In 1900, the German physicist Max Plancki proposed a single relationship between the energy and frequency of the emitted radiation that worked for all frequencies. Plank proposed that a heated solid could emit (or absorb) electromagnetic energy only in certain discrete amounts. The smallest amount of energy, called a quantum, is defined by the relationship E is energy of the radiation, visits frequency, and h is a constant called Planck's constant (6.626 x 10-34 J s). Planck's quantum hypothesis states that energy can be absorbed or emitted only as a quantum or as some whole multiple of a quantum i e. 1hv, 2hv, 3hv, and so on According to the above hypothesis, the atom itself must have only certain electronic energy values ie. 1hv, 2hv, 3hv and so forth to match the absorbed or emitted energy of light. The energy of an atom is quantized ie. it exists only in certain fixed amounts. Each change ofenergy is a result from a "packet" of energy