(a) Obtain the expression for the magnetic energy stored in a solenoid in terms of magnetic field B, area A and length l of the solenoid. (b) How does this magnetic energy compare with the electrostatic energy stored in a capacitor?

Derive the expression for the magnetic energy stored in a solenoid in terms of magnetic field B, area A and length l of the solenoid carrying a steady current 1. How does this magnetic energy per unit volume compare with the electrostatic energy density stored in a parallel plate capacitor ?

The expression for the energy stored in a capacitor is

The total electrostatic energy stored in both the capacitor is