quantum mechanics - Why doesn't the electron lose or absorb energy while remaining in a selected orbit?

Postulate 2: When an electron revolves in any selected orbits, it neither emits nor absorbs energy . The energy of an electron in a particular orbit remains constant.

Thus, Bohr, by postulating this, removed the problems of Rutherford's atomic model as:

If the negatively charged electron revolves round the positive nucleus, it will continuously emit radiations. Thus, it will follow a spiral path and eventually will collapse. If it happens, the spectra of the atom should be continuous as it will radiate at all the frequences while collapsing. But, in practice, this doesn't happen and atom is stable.

1. 
   

   How?

   
   


2. 
   

   By postulating a statement, how could he solve the problem?

   
   


3. 
   

   What is the cause for his statement being correct?

   
   
   


4. 
   

   Why doesn't the electron lose or gain energy?

   
   


5. 
   

   Does electron follow his postulate?

   
   


6. 
   

   Or is there any physical intuition behind it?

   
   

Please help. (please give me a math-free explanation. I want the physical intuition.)