Zeeman effect is the splitting of a spectral line in presence of the magnetic field.
What is the Zeeman effect?
The Zeeman effect is the splitting of the spectral lines of an atom in the presence of a strong magnetic field. The effect is due to the distortion of the electron orbitals because of the magnetic field. The atomic energy levels, the transitions between these levels are influenced by a magnetic field. If there are magnetic fields present, the atomic energy levels are split into a more extensive number of levels and the spectral lines are also split. This splitting is called the Zeeman Effect.