Plank Quantum Theory :
In 1900 a German physicist Max Plank presented his theory about light, called plank quantum theory. This theory has the following postulates: -
(1) Light is not emitted or absorbed continuously.
Light is emitted or absorbed in the form of packets of energies, which are called photon or quantas.
2; Each packet is associated with definite amount of energy , which is directly proportional to fhe frequency of radiation.
E = hn nis the frequency and h is plank constant
3; This is called plank equation and h is plank constant the value of which is 6.626x 10-34 Jsec
4; The energy emitted or absorbed by a body is always whole number multiple of quantum . i.e. En = n hn