Write the characteristics of photons.

Explanation

According to particle nature of light, photons are the basic constituents of any radiation and possess the following characteristic properties :
(i) The photons of light of frequency `upsilon` and wavelength `lambda` will have energy, given by `E = h upsilon = (hc)/(lambda)`
(ii) The energy of a photon is determined by the frequency of the radiation and not by its intensity and the intensity has no relation with the energy of the individual photons in the beam.
(iii) The photons travel with the velocity of light and its momentum is given by `p = (h)/(lambda) = (h upsilon)/(c)`
(iv) Since photons are electrically neutral, they are unaffected by electric and magnetic fields.
(v) When a photon interacts with matter (photon-electron collision), the total energy, total linear momentum and angular momentum are conserved. Since photon may be absorbed or a new photon may be produced in such interactions, the number of photons may not be conserved.