Final answer:
The Zeeman effect is the splitting of spectral lines when a magnetic field is applied. It is a result of quantized energy levels in atoms.
Step-by-step explanation:
The Zeeman effect is the splitting of spectral lines when a magnetic field is applied. It is a result of quantized energy levels in atoms. The quantization of orbital angular momentum and the intrinsic spin of electrons both contribute to the Zeeman effect.