Students investigate the efficiency of an electric motor - Edexcel - GCSE Physics - Question 4 - 2018 - Paper 1
Question 4
Students investigate the efficiency of an electric motor.
(a) The students measure the input power and the output power of the motor. Complete the sentence by putti... show full transcript
Worked Solution & Example Answer:Students investigate the efficiency of an electric motor - Edexcel - GCSE Physics - Question 4 - 2018 - Paper 1
Step 1
Complete the sentence by putting a cross (X) in the box next to your answer.
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Answer
The power of the motor is the rate of transfer of C energy.
Step 2
Sketch a graph for an alternating current of frequency 0.5 Hz.
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Answer
The graph for an alternating current of frequency 0.5 Hz will show a sine wave oscillating between positive and negative values. The x-axis represents time in seconds, while the y-axis represents current in amperes. The wave will complete one full cycle in 2 seconds, due to the frequency being 0.5 Hz.
Step 3
Explain what is meant by an efficiency of 40%.
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Answer
An efficiency of 40% means that 40% of the electrical energy supplied to the motor is converted into useful mechanical energy, while the remaining 60% is lost as waste energy, often in the form of heat due to friction and other factors.
Step 4
Calculate the energy supplied to the motor in 3 minutes. State the unit.
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Answer
To calculate the energy supplied to the motor:
Convert the time from minutes to hours: 3 minutes = 3/60 = 0.05 hours.
