Neil's Bohr'sTheory:

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Neil Bohr in 1913, gave his idea of line spectra.

The main postulates are:

1. Electrons revolve round the nucleus in fixed orbits or energy levels.
2. The electrons moving in a fixed orbit have fixed energy.
3. The electrons in an atom move only in certain energy levels, so an electron in allowed energy state will not radiate energy and there fore will not fall in the nucleus.
4. An electron absorbs energy to go to higher orbit and radiates energy as a light only when electron jumps from higher energy level to lower energy level.
5. The quantity of energy radiated is in discrete quantity, called Quanta. A quantum of energy is directly proportional to the frequency of the radiation.

where............... h = Plank's constant.
..........................v= is frequency of the radiation.
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