Question

Energy needed to establish an alternating current I in a coil of self-inductance L is

Options

• `L (dI)/(dt)`

• `1/2 LI^2`

• `1/2 IL^2`

• zero

Answer 1

`1/2 LI^2`

Explanation:

Inductance L opposes current growth because the work required is `1/2 LI^2`