Niels Bohr, a Danish physicist applied Planck"s ideas, and realised that the energy levels were quantised but in a more complicated way, going as n2...

Niels Bohr, a Danish physicist applied Planck"s ideas, and realised that the energy levels were quantised but in a more complicated way, going as n2 rather than n. We will see exactly why this is later, but for now, is there any proof for Bohr"s ideas and what does de Broglie have to do with it all?