Welcome to the Quiz!
This quiz contains 18 questions from a mix of 1 subtopics.
What is the primary function of a transformer?
to convert AC to DC
to step up or step down AC voltages
to rectify AC
to change the frequency of AC
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In a transformer, what is the component that links the primary and secondary coils?
copper wire
alternating current
insulation
iron core
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Which law explains the principle of electromagnetic induction in transformers?
ohm's law
kirchhoff's law
faraday's law
lenz's law
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What happens to the magnetic flux in the iron core when an alternating current flows through the primary coil?
it reverses direction
it becomes zero
it remains constant
it alternates
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According to Faraday's law, the magnitude of the induced e.m.f. in a coil is directly proportional to:
the current in the coil
the resistance of the coil
the rate of change of magnetic flux linkage
the number of turns in the coil
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A transformer has 200 turns on its primary coil and 600 turns on its secondary coil. If the input voltage is 120 V, what is the output voltage?
360 V
120 V
40 V
720 V
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In an ideal transformer, which of the following is true?
current input equals current output
efficiency is always less than 100%
power input equals power output
voltage input equals voltage output
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If the number of turns on the secondary coil is greater than the number of turns on the primary coil, the transformer:
steps down the voltage and decreases the current
steps up the voltage and decreases the current
steps up the voltage and increases the current
steps down the voltage and increases the current
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Why are high voltages used in electrical power transmission?
to increase the current in the transmission lines
to minimise power losses in transmission cables
to decrease the resistance of the transmission lines
to increase power losses in transmission cables
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Explain the role of the primary and secondary coils in a transformer.
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How do transformers enable efficient electrical power transmission over long distances?
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A transformer has 150 turns on its primary coil and 450 turns on its secondary coil. If the primary voltage is 110 V, calculate the output voltage from the secondary coil.
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If a step-down transformer reduces the voltage from 240 V to 24 V, and the primary coil has 600 turns, how many turns are there on the secondary coil?
turns
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A transformer has 150 turns on its primary coil and 450 turns on its secondary coil. If the input (primary) voltage is 120 V, what is the output (secondary) voltage?
480 V
360 V
40 V
240 V
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A step-down transformer decreases the voltage from 240 V to 60 V. If the primary coil has 200 turns, how many turns are there on the secondary coil?
800 turns
100 turns
150 turns
50 turns
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If a transformer's efficiency is 90% and the input power is 1000 W with a primary voltage of 200 V, what is the secondary current if the secondary voltage is 50 V?
18 A
22.5 A
20 A
25 A
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A step-up transformer increases the input voltage from 110 V to 220 V. What is the ratio of turns between the secondary and primary coils?
4:1
1:1
2:1
1:2
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In an electrical power transmission system, a transformer steps up the voltage from 230 V to 13,800 V for efficient transmission. If the primary coil has 100 turns, how many turns does the secondary coil have?
6,000 turns
60,000 turns
3,000 turns
600 turns
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