# Question #a0dfc

##### 1 Answer

Feb 4, 2017

You can do it like this:

#### Explanation:

If we consider the electron as a standing wave then an integral number of wavelengths must fit into one circular orbit:

From de Broglie we get:

Substituting for

The angular momentum is given by

This shows the angular momentum to be quantised, where **n** is the principal quantum number.