2022 · Specimen · 9702/04 | Q3

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Available practice: 77 of 100 marks. Parts 1(b), 4(b)(i), 4(c), 6(a)(ii), 6(b)(ii), 7(a)(i), 7(a)(ii), 9(b)(i), 9(c), 10(b)(ii) await marking support. Scores cover available parts only.

A bar magnet of mass 250 g is suspended from the free end of a spring, hanging so that one pole is near the centre of a coil of wire; the coil is connected in series with a resistor and an open switch. The magnet is displaced vertically and then allowed to oscillate. At time t = 0 the magnet is oscillating freely; at t = 6.0 s the switch is closed.

(a)(i)For the oscillating magnet, use data from Fig. 3.2 to determine, to two significant figures, the frequency f.

Fig. 3.1 — see the question text for what it shows

Fig. 3.2 — see the question text for what it shows

[2 marks]

A bar magnet of mass 250 g is suspended from the free end of a spring and oscillates vertically; one pole is near the centre of a coil connected in series with a resistor and a switch. At t = 0 the magnet oscillates freely; at t = 6.0 s the switch is closed.

(a)(ii)For the oscillating magnet, use data from Fig. 3.2 to determine, to two significant figures, the energy of the oscillations during the time interval t = 0 to t = 6.0 s.

[3 marks]

A bar magnet of mass 250 g suspended from a spring oscillates with one pole near the centre of a coil connected in series with a resistor and a switch. At t = 6.0 s the switch is closed.

(b)When the switch is closed, the oscillations are damped. Explain, with reference to Fig. 3.2, whether this damping is light, critical or heavy.

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Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.

[1 mark]

9702/04/SP/22Cambridge International AS & A Level Physics 9702 · Specimen 2022 · Paper 4 · Question 3