Find the number of waves made by a Bohr electron in one complete revolution in the 3rd orbit.

Explanation

The number of waves in any orbit `= ("circumference")/("wavelength")=(2pir)/(lambda)=2pir xx(mv)/(h)`
 The angular momentum of 3rd orbit is `(3h)/(2pi)`
Number of waves `=(2pi)/(h)xx(3h)/(2pi)=3`