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

• A. 13.89 H
• B. 0.138 H
• C. 1.389 H
• D. 138.88 H

Answer 1

The Correct Option is A

To find the inductance L of an inductor, we can use the formula for the magnetic potential energy stored in an inductor:

The magnetic potential energy U stored in an inductor is given by:

U = \frac{1}{2} L I^2

where:

• U is the magnetic potential energy,
• L is the inductance,
• I is the current flowing through the inductor.

Given:

• U = 25 \, \text{mJ} = 25 \times 10^{-3} \, \text{J}
• I = 60 \, \text{mA} = 60 \times 10^{-3} \, \text{A}

We need to find L. Rearrange the formula to solve for L:

L = \frac{2U}{I^2}

Substitute the given values into the formula:

L = \frac{2 \times 25 \times 10^{-3}}{(60 \times 10^{-3})^2}

L = \frac{50 \times 10^{-3}}{3600 \times 10^{-6}}

Simplifying further:

L = \frac{50}{3.6} \, \text{H}

Calculating gives:

L = 13.89 \, \text{H}

Therefore, the inductance of the inductor is 13.89 H.