Figure 12 shows some hair straighteners - AQA - GCSE Physics - Question 11 - 2022 - Paper 1
Question 11
Figure 12 shows some hair straighteners.
Hair straighteners contain heating elements.
Figure 12
When the hair straighteners reach normal operating temperature, an ... show full transcript
Worked Solution & Example Answer:Figure 12 shows some hair straighteners - AQA - GCSE Physics - Question 11 - 2022 - Paper 1
Step 1
Draw the circuit symbol for an LED
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Answer
The circuit symbol for an LED consists of a diode symbol with two arrows pointing away from it, indicating emission of light. In the box, draw a diode symbol with arrows to signify that it is an LED.
Step 2
Why do the hair straighteners not turn on when only switch S2 is closed?
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Answer
When only switch S2 is closed, there is a gap in the circuit, meaning that the circuit is incomplete. Therefore, the hair straighteners do not receive power and cannot turn on.
Step 3
Calculate the time taken for the hair straighteners to reach normal operating temperature when operating at maximum power.
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Answer
To find the time, we use the formula:
E=Pimest
where
E is the energy (3600 J)
P is the power (120 W)
Rearranging the formula gives:
t=PE=1203600
Thus, the time taken is:
t=30extseconds.
Step 4
Explain what happens to the power output of the power supply when switches S2 and S3 are closed at the same time.
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Answer
When switches S2 and S3 are closed, the total resistance of the circuit decreases due to additional parallel paths. This increased current results in a higher power output from the power supply, as power is given by the formula:
P=I2R
Thus, more power is delivered to the hair straighteners.
