Derivation of potential energy for Bohr's atomic model

Question

I am trying to derive the total energy of the electron in Bohr's stationary orbit but I am finding it hard to derive the potential energy, i.e. how the potential energy is derived from the equation $$PE=-k \frac{Ze^2}{r}~?$$

Answer 1

For two point charges $q$ and $Q$ separated a distance $r$ the potential energy is

$$ U = -\frac{k q Q}{r} $$

Now, make $Q = Ze$ and $q = e$, you get

$$ U = -\frac{k Ze^2}{r} $$