Question

Starting from the expression for the energy W = (1/2)LI², stored in a solenoid of self-inductance L to build up the current I, obtain the expression for the magnetic energy in terms of the magnetic field B, area A and length I of the solenoid having n number of turns per unit length. Hence show that the energy density is given by B²/2μ₀.

Comments

B² kaise aaya

Answer 1

Given:

Energy  W = (1/2) LI² 

A solenoid having magnetic field B, area A, & length I and having n numbers of turns per unit length. I Self-inductance of the solenoid is given by :