4.5. Electromagnetic effects
A subsection of Physics, 5054, through 4. Electricity and magnetism
Listing 10 of 237 questions
A simple apparatus used to demonstrate electromagnetic induction is shown in . S N magnet coil movement spring support LED The coil is connected to two light-emitting diodes (LEDs). The magnet moves into and out of the coil. Explain why there is an induced e.m.f. in the coil when the magnet moves. Explain why one LED lights up when the magnet moves into the coil and the other LED lights up when the magnet moves out of the coil. The LEDs are brighter when the magnet moves faster. Explain why.
5054_s15_qp_21
THEORY
2015
Paper 2, Variant 1
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Induced currents can be formed in a coil of wire by electromagnetic induction. Describe how to demonstrate the formation of an induced current in a coil of wire. Sketch and label a diagram of the arrangement of the apparatus. State two changes to the apparatus that increase the induced current. 1. 2. The direction of the induced current is determined by Lenz’s Law. 1. State Lenz’s Law. 2. Describe how Lenz’s Law applies in the experiment you described in . An electrical generator supplies power to a distant factory. The factory receives 500 kW of electrical power at a voltage of 33 kV. Calculate 1. the current in the wires supplying the power, current = 2. the electrical energy supplied to the factory in one hour. energy = The 33 kV voltage supplied to the factory is very high. Transmitting electrical energy at high voltage reduces energy losses in the transmission lines. Explain why.
5054_s16_qp_21
THEORY
2016
Paper 2, Variant 1
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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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Questions Discovered
237