What is inductance?

• A. The property of a circuit which tends to oppose a change in the existing current
• B. The rate at which energy is transferred in a circuit
• C. The ability of a conductor to store electrical charge
• D. The measure of resistance at a given temperature

Answer: (A)

Inductance is the property of a circuit that tends to oppose changes in current. When current changes, it creates a changing magnetic field that induces a voltage that acts to oppose that change, described by v = L di/dt, where L is the inductance. Energy is stored in the magnetic field as E = 1/2 L I^2, linking inductance to both opposition to current change and magnetic energy storage. This is why the best choice says the circuit tends to oppose a change in existing current. The other ideas refer to power transfer (rate of energy, not opposition), capacitance (storing charge), and resistance (ohmic behavior at temperature), which are not what inductance describes.