A current of 1.0 A is established in a tightly wound solenoid of radius 2 cm having 1000 turns/metre. Find the magnetic energy stored in each metre of the solenoid.

Explanation

Here`1=1.0A, r=2cm,`
`n=1000 turns//m`
Magnetic energy stored `=(B^(2)V)/(2 (mu_0))`
[Where B- Magnetic field, V-Volume of soleniod]
`=(B^(2)V)/(2(mu_0))`
=4(pi)xx(10^(-7)xx10^(-6)xx1xxpixx4xx10^(-4)xx1)/(2)`
`=8 pixx10^(-5)=78.956xx10^(-5)`
=7.9xx10^(-4) J`.