In an electric circuit, what is the main effect of an inductor?

In an electric circuit, what is the main effect of an inductor?

• A. It stores energy in a capacitor
• B. It converts AC to DC
• C. It resists changes in current
• D. It reduces resistance

Answer: (C)

Inductors primarily resist changes in current. When current flows, a magnetic field builds around the coil; if the current tries to change, the changing magnetic flux induces a voltage that opposes that change (Lenz’s law). That opposing action is why the main effect is to slow how quickly current can rise or fall. The energy involved is stored in the magnetic field, and for a momentary current the stored energy is (1/2) L I^2. In steady direct current, an ideal inductor doesn’t “use up” energy; it simply allows current to continue with only its ohmic resistance. In alternating current, the inductor presents inductive reactance that grows with frequency, making it harder for high-frequency currents to pass. Storing energy in a capacitor would involve the electric field between plates, not a magnetic field. Converting AC to DC isn’t a function of an inductor, but of rectification. And an inductor doesn’t reduce resistance; it adds impedance due to its inductance and can even impede current more at higher frequencies.

Inductors primarily resist changes in current. When current flows, a magnetic field builds around the coil; if the current tries to change, the changing magnetic flux induces a voltage that opposes that change (Lenz’s law). That opposing action is why the main effect is to slow how quickly current can rise or fall. The energy involved is stored in the magnetic field, and for a momentary current the stored energy is (1/2) L I^2.

In steady direct current, an ideal inductor doesn’t “use up” energy; it simply allows current to continue with only its ohmic resistance. In alternating current, the inductor presents inductive reactance that grows with frequency, making it harder for high-frequency currents to pass.

Storing energy in a capacitor would involve the electric field between plates, not a magnetic field. Converting AC to DC isn’t a function of an inductor, but of rectification. And an inductor doesn’t reduce resistance; it adds impedance due to its inductance and can even impede current more at higher frequencies.