# Allowed energies for electrons in hydrogenic atoms

I have a question which may seem stupid, but I think I missing something here.

I see 2 equations describing allowed energies for electrons in hydrogenic atoms, being:
$$E = -\frac{hcRZ^2}{n^2}$$
And
$$E = -\frac{RZ^2}{n^2}$$
I assume that both are correct, but what makes the difference? Is it the same R for both of them? or the second R includes the h and c inside?
How would I tell the difference?

SpectraCat
I have a question which may seem stupid, but I think I missing something here.

I see 2 equations describing allowed energies for electrons in hydrogenic atoms, being:
$$E = -\frac{hcRZ^2}{n^2}$$
And
$$E = -\frac{RZ^2}{n^2}$$
I assume that both are correct, but what makes the difference? Is it the same R for both of them? or the second R includes the h and c inside?
How would I tell the difference?