## Answers

### This Is a Certified Answer

Actually, angular momentum value (**mvr=nh/2 pi**) not h/2pi.Coming to the point, Firstly, this formula was not derived by anyone. It was observed by BOHR from an **experiment. **Later it was proved by Albert Einstein with the help of De Broglie Equation. According to de Broglie,

Wavelength(w) = h/mv ---(I)

and from equation derived after de Broglie eqn:-

nw = 2 pi r ---------------(II)

where n is number of wave, w is de Broglie wavelength, r is radius of shell.From equation I and II,

n(h/mv) = 2 pi r (putting the value of w from eqn I to II)

After simplifying we get,

*Angular Momentum = mvr = nh/2 pi *

*PROVED*