Question

Calculate the number of waves made by a Bohr electron in one complete revolution in its third orbit.

Answer 1

Here we gooo.....


According to Bohr’s postulate of angular momentum, in the 3rd orbit

Mur = n h/2π

Mur = 3 (h/2π) …..(i) [n = 3]

According to de Broglie relationship

λ = h/mu ….(ii)

Substituting (ii) in (i), i get!


(h/λ) r = 3 (h/2π)
3λ = 2πr

Easy method!!


Number of waves = n(n - 1)/2
3(3 - 1)/2 = 3 * 2/2 = 3

hope it helps!!

Answer 2

Heya !!!

Here's the answer

Number of waves produced when an electron in nth orbit

$= \frac{n(n - 1)}{2} \: where \: n \: is \: the \: principal \\ \: quantum \: number$

So, for electron in 3rd orbit, number of waves
= 3(3-1)/2 = 3



HOPE THAT HELPS ☺️