Question

What is hydrogen spectrum?

Answer 1

According to Bohr, when an electron from its initial stationary orbit with n= ni jumps to another (lower) stationary orbit with n=nf, it emits energy equal to the difference between the energy of the two stationary orbits in the form of small packets of light known as photons. For every transition of the electron, there is a line in the spectrum and there are different types of spectral series formed. He gave the spectrum of Hydrogen ion which has one electron only, so this spectrum cannot be applied for atoms with more than one electron.

Answer 2

when the one and only electron jumps to the higher energy level and comes back to it's original position releasing some energy and it causes hydrogen spectrum