When the electrons of hydrogen atom return to L-shell from shell of higher energy, we get a series of lines in the spectrum. This series is called:

When the electrons of H-atom are de -exited from higher energy level to lower energy level i.e

'K' shell =Lymann

'L' shell=Balmer

'M' shell=Paschen

N' shell =Brackett

O' shell =Pfund