What energy form do inductors store?

• A. Electric field energy
• B. Magnetic field energy
• C. Kinetic energy
• D. Thermal energy

Answer: (B)

Inductors store energy in the magnetic field created by the current flowing through the coil. When current passes through the winding, it generates a magnetic field around it, and the energy associated with that field increases with the current. The stored energy for an inductor is given by W = (1/2) L I^2, where L is the inductance and I is the current. This magnetic energy is what makes inductors oppose changes in current, because increasing or decreasing the current requires adding or removing energy from the magnetic field.

Electric field energy, on the other hand, is stored in capacitors, not inductors. Kinetic energy relates to moving masses or charges and isn’t the energy stored in an inductor. Thermal energy is related to heat, which can arise as losses in an actual coil due to resistance, but the primary stored energy in an ideal inductor resides in its magnetic field.