State Planck’s law of radiation, Explain the terms “quantum” and “quantized”.

Q.       State Planck’s law of radiation.

Ans. The energy of electromagnetic radiation is composed of discrete quanta, the magnitude of which is given by the product of Planck's constant and the frequency of radiation.

Q.       Explain the terms “quantum” and “quantized”.

Ans.    According to the quantum theory, energy exists in

discrete units, only whole numbers of which can exist; each unit is called a quantum (plural ‘quanta’). The quantum of electromagnetic radiation is called photon.

A quantity is said to be quantized if, in accordance with quantum mechanics, it can only have certain discrete values. Such a quantity cannot vary continuously, differences in value being separated by 'jumps'.