4.5.3. Magnetic effect of a current
A subsection of Physics, 0625, through 4. Electricity and magnetism
Listing 10 of 188 questions
A student plans to demonstrate the induction of an electromotive force (e.m.f.) in a wire. He has a length of wire, a sensitive centre‑reading galvanometer and a permanent magnet. Describe how the student uses the equipment. State two ways in which the student can increase the size of the induced e.m.f. shows a d.c. motor. magnet coil rotation of coil battery current – + On , draw an arrow between the poles of the magnet to show the direction of the magnetic field. State two ways of making the coil spin faster. State one way of making the coil spin in the opposite direction.
0625_w21_qp_31
THEORY
2021
Paper 3, Variant 1
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shows a relay. contacts armature pivot primary circuit to secondary circuit C The statements describe the action of a relay. They are not in the correct order. P Current in the coil creates an electromagnet. Q Secondary circuit is completed. R Armature pivots, closing the contacts. S Part C attracts the armature. T The switch in the primary circuit is closed. Place the statements in the correct order. One has been done for you. S includes the part labelled C, which is made from a metal. State the name of the metal and explain why this metal is used in the electromagnet. metal explanation
0625_m19_qp_32
THEORY
2019
Paper 3, Variant 2
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The reed switch (reed relay) shown in is a normally-closed one. When a magnet is held close to the reed switch, the contacts open, as shown in . also includes the circuit symbol for a bell. N S Complete so that it shows a circuit that will cause the bell to ring when the magnet is taken away. shows a door in a wall. On Fig 11.3, show where you would fix the reed switch and the magnet of Fig 11.2, so that the bell rings when the door opens. Use the letter S for the switch and the letter M for the magnet. Suggest one application of this arrangement.
0625_w10_qp_21
THEORY
2010
Paper 2, Variant 1
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Describe what is meant by alternating current (a.c.). A teacher demonstrates how a loudspeaker works by using the equipment shown in . N coil paper cone strong magnet direction of vibration of paper cone S There is an alternating current in the coil. The paper cone and coil vibrate as shown in . Explain why the paper cone vibrates. Use your ideas about magnetism. When the paper cone vibrates, the teacher hears a sound. Suggest a value for the frequency of the alternating current. Include the unit. frequency = unit
0625_w23_qp_33
THEORY
2023
Paper 3, Variant 3
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Questions Discovered
188