A small particle of mass m mores in such a way that the potential energy where
is constant and r is the distance of the particle from the origin. Assuming Bohr's model of quantization of angular momentum and circular orbits, that radius of
allowed orbit is proportional to
n
The force at a distance r is -
suppose the particle moves along a circle of radius r. The net force on it showed be along the radius. Comparing with (i).
The quantization of angular momentum gives-
from (2) \& (3)