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9702/04/SP/22 · question 1 of 1 in this topic

Question 7

7(b)2 marks

A solenoid has a coil C of wire wound tightly about its centre. The coil C has 96 turns. The uniform magnetic flux Φ, in Wb, in the solenoid is given by the expression Φ = 6.8 × 10⁻⁶ × I, where I is the current, in A, in the solenoid.

Calculate the average electromotive force (e.m.f.) induced in coil C when a current of 3.5 A is reversed in the solenoid in a time of 2.4 ms.

Fig. 7.1 — see the question text for what it shows

Calculate Show your working. The method can earn marks even when the final value is wrong, and a bare answer often cannot.

Your answer

Suggested time: 3 min

7(c)2 marks

A solenoid has a coil C of 96 turns wound tightly about its centre, and the uniform magnetic flux in the solenoid is Φ = 6.8 × 10⁻⁶ × I where I is the solenoid current.

The d.c. supply in Fig. 7.1 is now replaced with a sinusoidal alternating supply.

Describe qualitatively the e.m.f. that is now induced in coil C.

Fig. 7.1 — see the question text for what it shows

Describe Say what happens, in order. Reasons are not required unless the question also asks why.

Your answer

Suggested time: 3 min

9702/04/SP/22Cambridge International AS & A Level Physics 9702 · Specimen 2022 · Paper 4 · sit the whole paper