CBSE NOTES CLASS 12 PHYSICS
CHAPTER 11 DUAL NATURE OF RADIATION AND MATTER
Photons are the packets of energy emitted by a source of radiation. The energy of each photon is,
E = hν,
where h is Planck’s constant and ν is frequency of radiation.
The rest mass of a photon is zero.
The momentum of a photon
Dynamic or kinetic mass of photon,
where c is speed of light in vacuum and λ is wavelength of radiation.
Photons are electrically neutral.
A body can radiate or absorb energy in whole number multiples of a quantum, that is hν, 2hν, 3hν …, nhν, where n is positive integer.