# Slope of Graph of Wave Number vs inverse square of the principal quantum number(1/n^2) in Hydrogen Emission spectrum

What is the final expression we get for wave number in a hydrogen emission spectrum? Let us say for example from 6 to an orbit $$n$$. Considering that it is an emission spectrum, I think it would be right to say $$n<6$$. And wave number is a positive quantity so I thought it would be $$R_h(\frac{1}{n^2}-\frac{1}{36})$$ and slope of the graph between wave number and $$\frac{1}{n^2}$$ would be $$R_h$$. But I would like to ask if it is right though. I recently wrote an exam who says the slope is $$-R_h$$, where $$R_h$$ is Rydberg's constant.

Thanks!

• There are no restrictions on how high $n$ can be. It can also be infinite and it's totally fine. Also, plotting continuous line across discrete data points is just wrong (you can estimate the slope though). – andselisk Jan 16 at 20:13