Writer Bohr's postulates for the hydrogen atom model.

Explanation

(i)An electron in an atom could revolve in certain stable orbits without the emission of radiant energy.
(ii) Electron revolves around the nucleus only in those orbits for which the angular momentum in some integral multiple of `h/(2pi)` where h=Planck.s constant .
`L=n.h/(2pi)`.
(iii)When an electron make a transition from one non- radiating orbit to another of lower energy a photon of energy is equal to the energy difference between the two states is emitted. i.e. `hv=E_i-E_f`.