These are :
(i)
Bohr’s first postulate was that an electron in an atom could revolve
in certain stable orbits without the emission of radiant energy,
contrary to the predictions of electromagnetic theory According to
this postulate, each atom has certain definite stable states in which it
Rationalised 2023-24
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Atoms
can exist, and each possible state has definite total energy These are
called the stationary states of the atom (ii) Bohr’s second postulate defines these stable orbits