Electromagnetic induction Flashcards – Cambridge IGCSE (9–1) Physics 0972 (Extended) (2026–2028)

What is electromagnetic induction?

The production of an e.m.f. in a conductor when it moves across a magnetic field or when the magnetic field linking it changes.

How do the circuit conditions for inducing an e.m.f. and driving an induced current differ?

An e.m.f. can be induced in an open or complete circuit, but it can drive a current only in a complete circuit.

How can electromagnetic induction be demonstrated using a coil, a bar magnet and a galvanometer?

Connect the coil to a sensitive galvanometer and move the magnet into and out of the coil.

What does the galvanometer deflection show when a magnet moves into or out of a coil?

A current is flowing due to an induced e.m.f.

What happens to the galvanometer deflection when the direction of a magnet’s motion relative to a coil is reversed?

The deflection reverses direction.

What happens to the galvanometer deflection when a magnet is held stationary relative to a coil?

It returns to zero.

What produces an induced e.m.f. in a coil during the moving-magnet demonstration?

A changing magnetic field linking the coil, not merely the presence of the magnet.

How does the rate of change of the magnetic field linking a conductor affect the induced e.m.f.?

A faster change produces a greater induced e.m.f.

How does speed affect the induced e.m.f. in a conductor or coil moving across a magnetic field?

Faster motion produces a greater induced e.m.f.

How does magnetic field strength affect the induced e.m.f. in a conductor or coil moving across the field?

A stronger magnetic field produces a greater induced e.m.f.

How does the number of turns affect the induced e.m.f. in a coil when each turn experiences the same change in magnetic field?

More turns produce a greater induced e.m.f.