Question

If the current through an inductor increases from 2 A to 3 A, the magnetic energy stored in the inductor increases by

• A. 125%
• B. 225%
• C. 50%
• D. 75%

Hint:

The magnetic energy stored in an inductor depends on the square of the current.

Answer 1

The Correct Option is A

The energy stored in an inductor is given by: \[ U = \frac{1}{2} L I^2 \] Initial energy: \[ U_1 = \frac{1}{2} L (2^2) = 2L \] Final energy: \[ U_2 = \frac{1}{2} L (3^2) = 4.5L \] Percentage increase: \[ \frac{U_2 - U_1}{U_1} \times 100 = \frac{4.5L - 2L}{2L} \times 100 \] \[ = \frac{2.5}{2} \times 100 = 125\% \] Thus, the correct answer is 125\%.