20.5. Electromagnetic induction
A subsection of Physics, 9702, through 20. Magnetic fields
Listing 10 of 56 questions
An incomplete diagram for the magnetic flux pattern due to a current-carrying solenoid is illustrated in . direction of current On , draw arrows on the field lines to show the direction of the magnetic field. State the feature of that indicates that the magnetic field strength at each end of the solenoid is less than that at the centre. A Hall probe is placed near one end of the solenoid in , as shown in . Y Hall probe to circuit for Hall probe X The Hall probe is rotated about the axis XY. State and explain why the magnitude of the Hall voltage varies. State Faraday’s law of electromagnetic induction. The Hall probe in is replaced by a small coil of wire connected to a sensitive voltmeter. State three different ways in which an e.m.f. may be induced in the coil. 1. 2. 3.
9702_w13_qp_42
THEORY
2013
Paper 4, Variant 2
View
A small coil is placed close to one end of a solenoid connected to a power supply. The plane of the small coil is normal to the axis of the solenoid, as illustrated in . solenoid small coil power supply The power supply causes the current I in the solenoid to vary with time t as shown in . t1 t2 time t current I State Faraday’s law of electromagnetic induction. On the axes of , sketch a graph to show the variation with time t of the electromotive force (e.m.f.) induced in the small coil. e.m.f. t1 t2 time t The small coil in is now replaced by a Hall probe. The Hall probe is positioned so that the reading for the probe is a maximum. The current I in the solenoid varies again as shown in . On the axes of , sketch a graph to show the variation with time t of the reading VH of the probe. time t VH t1 t2
9702_w20_qp_42
THEORY
2020
Paper 4, Variant 2
View
State Lenz’s law. A metal ring is suspended from a fixed point P by means of a thread, as shown in . P metal ring P metal ring magnet pole piece N S The ring is displaced a distance d and then released. The ring completes many oscillations before coming to rest. The poles of a magnet are now placed near to the ring so that the ring hangs midway between the poles of the magnet, as shown in . The ring is again displaced a distance d and then released. Explain why the ring completes fewer oscillations before coming to rest. The ring in is now cut so that it has the shape shown in . Explain why, when the procedure in is repeated, the cut ring completes more oscillations than the complete ring when oscillating between the poles of the magnet.
9702_s21_qp_41
THEORY
2021
Paper 4, Variant 1
View
State Lenz’s law. A metal ring is suspended from a fixed point P by means of a thread, as shown in . P metal ring P metal ring magnet pole piece N S The ring is displaced a distance d and then released. The ring completes many oscillations before coming to rest. The poles of a magnet are now placed near to the ring so that the ring hangs midway between the poles of the magnet, as shown in . The ring is again displaced a distance d and then released. Explain why the ring completes fewer oscillations before coming to rest. The ring in is now cut so that it has the shape shown in . Explain why, when the procedure in is repeated, the cut ring completes more oscillations than the complete ring when oscillating between the poles of the magnet.
9702_s21_qp_43
THEORY
2021
Paper 4, Variant 3
View
Questions Discovered
56