How to understand the concept of Magnetization ? in this video lecture I have explain about the electron spin magnetic moment and its effect in the presence of external magnetic field. How electron spin magnetic moment interact with the magnetic field and how an energy level break ups in to the two parts. What is spectroscopic splitting factor and how to calculate the value of its for a given atom (L, S, and J) where L is for the total orbital angular momentum, S spin angular Momentum and J is the total angular momentum.