# Rydberg constant

I derived the Rydberg constant with the help of Bohr model but I read on the internet that we have to assume the mass of nucleus to be infinitely larger than the electron's. However, I got the answer without any assumption and stuff.

My question is, what is the point of making that assumption. I just used Coulomb's law and quantization of angular momentum.

• Coulomb's law applied to a circular orbit (fitting of wavelengths) implies this assumption. So you did use it, but you didn't recognize it. – John Alexiou Oct 4 '17 at 12:57
• Fitting of wavelengths? I didn't get that – Utkarsh Mishra Oct 4 '17 at 18:16
• The orbiting electron has a De-Broglie wavelength $\lambda = {\rm h} / p$ and an integer number of wavelengths have to fit in the orbit. This is the quantization of momentum simplified. – John Alexiou Oct 4 '17 at 20:08