A 100 millihenry coil carries a current of 1A. Energy stored in its magnetic field is
0.5 J
1 A
0.05 J
0.1 J
Correct answer: 0.5 J
Solution
The energy stored in the magnetic field of an inductor is given by the formula U = (1/2)LI², where L is the inductance and I is the current. Substituting L = 100 mH = 0.1 H and I = 1 A, we get U = (1/2)(0.1)(1)² = 0.05 J.