4.5.2. The a.c. generator
A subsection of Physics, 5054, through 4. Electricity and magnetism
Listing 10 of 30 questions
shows the structure of a simple alternating current (a.c.) generator. output terminals On , label • the coil of the generator with the letter C, • a slip ring with the letter S, • a carbon brush with the letter B. The a.c. generator is operating and the arrows on show the direction of rotation. Explain why there is an electromotive force (e.m.f.) between the two output terminals. The output terminals of the a.c. generator are connected to a cathode-ray oscilloscope (c.r.o.). shows the trace on the screen of the c.r.o. Describe how the trace and a setting on the c.r.o. are used to find the time for one revolution of the coil of the a.c. generator. You may draw on if you wish.
5054_w14_qp_22
THEORY
2014
Paper 2, Variant 2
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An alternating current (a.c.) generator is used in a remote location to supply electricity. shows the structure of a simple a.c. generator with the coil horizontal. S N output terminals rotation horizontal coil P Q State the name of the components labelled P and Q on . P Q When the generator is producing an electrical output, P is stationary and Q is rotating. Explain the purpose of P and Q. The output of the generator is connected to an oscilloscope. On the oscilloscope the Y-gain is set at 5.0 V / cm and the timebase setting is 2.0 ms / cm. shows the trace on the screen of the oscilloscope. 1 cm 1 cm trace Write a letter X on the trace shown in to indicate one point when the coil is vertical. Using , determine the maximum value of the e.m.f. produced by the generator. maximum e.m.f. = V Using , determine, in milliseconds, the time it takes for one revolution of the coil. time for one revolution of the coil = ms Determine the frequency of the output of the generator. frequency = Hz
5054_w23_qp_21
THEORY
2023
Paper 2, Variant 1
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Questions Discovered
30