Can you please provide detailed explanation for correct answer for attached question . Thanks

 

1) electrons revolve round the nucleous only in certain permissible circular orbirts , also called shells.

 

2)each orbit is associated with adefinate energy.

 

3) the energy of an electron remains constant as long asit revolves in a given orbit.

 

4)when electron absorbs energy, it jumps from a low -energy level to a high-energy level.

 

5)but, electron at higher energy level is unstable . so, it jumps from higher energy level to lower energy level and gives out energy. 
(6) Angular momentum of electrons revolving in an orbit is given by= n*h/2π ( where n- orbit number) 
Now if equate the formula for angular momentum 'L' =mv²r
Where, m= mass ; v= velocity & r=radius of orbit
equatting the two we get,
mv²r=nh/2π
r = nh/(2*π*m*v²) 
r = L /m*v²    ( since nh/2π=L) 
From the above it is clear that (1) is false and (2) is true
Thus, option d is correct. 
Regards