In electrical energy storage, which field is associated with an inductor?

• A. Electric field
• B. Thermal field
• C. Magnetic field
• D. Gravitational field

Answer: (C)

Energy in an inductor is stored in the magnetic field produced by current flowing through its coil. When current passes through the winding, a magnetic field forms around it and links the turns, storing energy that grows with the current and the inductance. The stored energy is given by W = 1/2 L I^2, and the inductance L reflects the coil’s geometry and material. This magnetic field is also why inductors resist sudden changes in current, via the relationship V = L di/dt. The other fields mentioned don’t primarily store energy in an inductor: electric fields are linked to capacitors, thermal energy to heat, and gravitational fields aren’t a factor in typical electrical energy storage.