Question

The magnetic potential energy stored in a certain inductor is 25 mJ, when the current in the inductor is 60 mA. This inductor is of inductance ______.

Options

• 0.138 H

• 138.88 H

• 1.389 H

• 13.89 H

Answer 1

The magnetic potential energy stored in a certain inductor is 25 mJ, when the current in the inductor is 60 mA. This inductor is of inductance 13.89 H.

Explanation:

Magnetic potential energy (u) = 25 mJ = 25 × 10^-3 J

Now, current flowing in the unductor (I) = 60 mA = 60 × 10^-3 A

Magnetic potential energy stored in an inductor is given by u = (1/2)L × I²

25 × 10^-3 = (1/2) × L × (60 × 10^-3)²

L = (50 × 10^-3)/(3600 × 10^-6)

= (50 × 10³)/3600

= 13.89 H