Question

bohr postulate to define stable orbits in hydrogen atom

Answer 1

Hope it helps..
and sorry for bad handwriting..

Answer 2

As per Rutherford's atomic model, the electrons are revolving around the nucleus just like planets are revolving around the sun. But, this model could not explain the stability of atom as it was against Clark Maxwell' s electromagnetic theory.

It states that any charged particle under accelerated motion will emit energy. If that happens, the electron will come closer and closer to the nucleus, and finally, it will fall inside the nucleus for which the total atom will be destroyed.

Bohr modified this theory and uniquely defined the stability of atom.

As per Bohr's theory, the electrons are revolving around nucleus in different stationary orbits.

2- As long as electrons are present on the orbits, there will be no emission or absorption of energy. Hence, the energy of the electrons in a particular orbit is constant.

3- Only those orbits are permitted to the electrons in which the angular momentum is the integral multiple of  $\frac{nh}{2\pi}$

Here n stands for orbit number and h is the Planck's constant.