Inductance in a coil is a property that ...

• A. It stores energy in a magnetic field
• B. It reduces resistance in a circuit
• C. It accelerates current changes
• D. It opposes change in current flow through a coil

Answer: (D)

Inductance describes how a coil resists changes in current. When the current in a coil tries to change, the changing magnetic field induces a voltage that acts to oppose that change, a relation captured by v = L di/dt. So the coil behaves like a brake on rapid increases or decreases in current, which is why it is said to oppose changes in current flow through the coil. It’s true that inductors store energy in a magnetic field (the energy is (1/2)LI^2), but the defining action described by inductance is this opposition to changing current. It does not inherently reduce resistance, and it does not accelerate current changes; it resists them.