CAIE IGCSE Physics Electromagnetic Induction Overview

Practise explaining and investigating induced voltage, predicting how its magnitude and direction change, and applying field–motion–current directions.

Exam points

identify an induced e.m.f. when a conductor cuts field lines or changing flux links a coil
predict a larger reading from faster motion, a stronger field or more turns, and zero for no flux change
reverse motion or field to reverse induced current and apply the relative field–motion–current directions

Covered syllabus points

4.5.1.1—A conductor moving across a magnetic 4.5.1.2—An experiment to demonstrate EM 4.5.1.3—Factors affecting the magnitude of an 4.5.1.4—Direction of an induced e.m.f. opposes 4.5.1.5—And use the relative directions of

[Maximum number: 3]

Fig. 10.1 shows a simple alternating current generator.

Fig. 10.1

(a)

Explain why an e.m.f. is induced only when the coil is turning.

[ 1 ]

(b)

State two possible changes that cause a larger e.m.f. to be induced.
1.
2.

[ 2 ]

[Maximum number: 6]

Fig. 9.1 shows a permanent bar magnet next to a circuit that contains a coil and a galvanometer.

Fig. 9.1

(a)

The magnet is moved to the left and inserted a small distance into the coil. The galvanometer deflects briefly and shows that there is a current in the coil.

[ 4 ]

(i)

Explain why there is a current in the coil.

[ 2 ]

(ii)

As the magnet is moving near to the coil, end Q of the coil behaves as a magnetic pole. State the polarity of end Q and explain why it has this polarity.

[ 2 ]

(b)

Suggest two ways in which the deflection of the galvanometer can be reversed.
1.
2.

[ 2 ]

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Covered syllabus points

4.5.1 Electromagnetic induction question 1

Question (a)

Question (b)

4.5.1 Electromagnetic induction question 2

Question (a)

Question (i)

Question (ii)

Question (b)