4.5.3. Magnetic effect of a current
A subsection of Physics, 5054, through 4. Electricity and magnetism
Listing 10 of 29 questions
Use shows a coil of wire wound on a cardboard tube. There is a d.c. current in the coil. The direction of the current is shown in the key. wire with current into page key wire with current out of page cardboard tube On , draw the magnetic field produced by the coil. shows a simple loudspeaker that uses the coil shown in attached to a paper cone. coil paper cone permanent magnet N S The coil is connected to a signal generator. There is an alternating current of frequency 100 Hz in the coil. State what is meant by a frequency of 100 Hz. Examiner’s Use Describe and explain the movement of the coil.
5054_s07_qp_2
THEORY
2007
Paper 2, Variant 0
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shows the structure of a circuit-breaker that uses an electromagnet. The circuit-breaker operates when the current is 10 A. current in electromagnet iron bar pivot fixed bar copper bar spring pivot current out contacts On , mark with an arrow the force on the iron bar caused by the electromagnet. Suggest one reason why the iron bar does not move when the current is less than 10 A. When the current is greater than 10 A, the circuit-breaker stops the current. Explain what happens in the circuit-breaker when this occurs. State and explain how the electromagnet can be altered so that the circuit-breaker stops the current at less than 10 A.
5054_s11_qp_21
THEORY
2011
Paper 2, Variant 1
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shows part of a loudspeaker. A coil is attached to a paper cone and is suspended freely within a cylindrical magnet. N S N paper cone cylindrical magnet coil current Explain why a current in the coil causes the paper cone to move. Describe and explain the movement of the cone when there is an alternating current in the coil. The loudspeaker produces sound of frequency 500 Hz. The speed of sound is 320 m / s. Calculate the wavelength of the sound produced. wavelength =
5054_s16_qp_21
THEORY
2016
Paper 2, Variant 1
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shows a coil of wire wound around a rectangular tube. Two iron rods are placed next to each other at the bottom of the tube. When the current is switched on, the two rods repel each other. They move to the sides of the tube. Explain why the two iron rods repel. An iron rod and a similar copper rod are placed next to each other at the bottom of the tube. State and explain what, if anything, happens to the rods when the current is switched on. coil tube iron rods Use
5054_w05_qp_2
THEORY
2005
Paper 2, Variant 0
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Questions Discovered
29