An inductor resists changes in current by generating an electromotive force (emf) that opposes the change. This emf is called what?

An inductor resists changes in current by generating an electromotive force (emf) that opposes the change. This emf is called what?

• A. Electrical resistance
• B. Magnetic flux
• C. Capacitance
• D. Electromotive force (emf)

Answer: (D)

An inductor resists changes in current by generating an electromotive force inside the coil. This induced emf is the electromotive force (emf) that acts to oppose the change in current, a manifestation described by Faraday’s law and Lenz’s law. In math terms, emf = -L di/dt, meaning the emf arises specifically because the current is changing. In practice, this emf is often referred to as back emf because its direction opposes the change in current. The other terms aren’t what the inductor produces in response to a changing current: resistance is a property that slows current without being an induced voltage, magnetic flux is the changing quantity that gives rise to the emf, and capacitance relates to energy storage in electric fields, not inductive opposition.

An inductor resists changes in current by generating an electromotive force inside the coil. This induced emf is the electromotive force (emf) that acts to oppose the change in current, a manifestation described by Faraday’s law and Lenz’s law. In math terms, emf = -L di/dt, meaning the emf arises specifically because the current is changing. In practice, this emf is often referred to as back emf because its direction opposes the change in current. The other terms aren’t what the inductor produces in response to a changing current: resistance is a property that slows current without being an induced voltage, magnetic flux is the changing quantity that gives rise to the emf, and capacitance relates to energy storage in electric fields, not inductive opposition.