State the three postulates of Bohr's theory of hydrogen atom.

Explanation

(a)An electron cannot revolve round the nucleus in any arbitrary orbit . Only certain orbits are permitted. Electron does not radiate energy in stationary orbits.
(b)The radius of the allowed electron orbits is determined by the quantum condition It states that the orbital angular momentum of electron about the nucleus is an integral multiple of `h/(2pi)`
According to Bohr.s postulate ,
`mvr=n(h/(2pi))`
( c) An atom radiates energy only when an electron jumps from a higher energy orbit to a lower energy orbit. If `E_1` and `E_2` are the lower and higher energies and v is the frequency of radiation , then `v=(E_2-E_1)/h`.