Electromagnetic (EM) Induction Flashcards

All 7 cards in this deck

What is the generator effect?

When a conductor moves relative to a magnetic field, or the magnetic field around a conductor changes, a potential difference is induced across the ends of the conductor.

What extra condition is needed for an induced potential difference to produce an induced current?

The conductor must be part of a complete circuit.

What three factors increase the size of the induced potential difference in a coil?

Moving faster (faster rate of change of field), a stronger magnetic field, and more turns on the coil.

What two things determine the direction of an induced potential difference or current?

The direction the conductor moves and the direction (polarity) of the magnetic field. Reversing either one reverses the induced current.

What is the direction of the magnetic field produced by an induced current?

It opposes the original change — either the movement of the conductor or the change in the magnetic field.

True or false? A generator becomes harder to turn when a lamp is connected across it.

True. The induced current produces a magnetic field that opposes the movement of the coil.

True or false? A potential difference is induced in a coil when a magnet is held still inside it.

False. The magnetic field must be changing (or the conductor moving) for a potential difference to be induced.