Which Bohr postulate explains the stability of the

Solution

Bohr postulated that an electron in a hydrogen atom revolves in certain fixed orbits (energy levels) where it does not emit electromagnetic radiation , despite being under acceleration. This idea resolved the classical contradiction which predicted that the electron should continuously lose energy and spiral into the nucleus. The non-radiating stationary orbits explain why the atom remains stable and does not collapse. ●      (A) Incorrect : While angular momentum quantization explains the allowed orbits, it doesn't directly explain why the atom doesn't radiate energy in these orbits.

●      (B) Incorrect : Bohr’s model explains line spectra , not continuous spectrum. Emission is quantized, not continuous.

●      (D) Incorrect : Classical mechanics could not explain atomic stability; it predicted atomic collapse due to radiation from accelerated charges.

Thus, Bohr's postulate of discrete energy levels with no radiation in stable orbits (C) best explains the stability of the hydrogen atom.