An inventor is designing a battery-powered torch - Edexcel - GCSE Physics - Question 3 - 2013 - Paper 1
Question 3
An inventor is designing a battery-powered torch. She wants the torch to have a brightness control.
Which of these could she use in this control?
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Worked Solution & Example Answer:An inventor is designing a battery-powered torch - Edexcel - GCSE Physics - Question 3 - 2013 - Paper 1
Step 1
Which of these could she use in this control?
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Answer
The best choice for a brightness control in a torch circuit is a variable resistor. This component allows the user to adjust the resistance in the circuit, thereby controlling the current flowing to the lamp and thus its brightness.
Step 2
Add a voltmeter to the circuit which will measure the potential difference (voltage) across the lamp.
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Answer
To illustrate the connection of a voltmeter to the circuit, the voltmeter should be connected in parallel with the lamp in the circuit. This allows it to measure the potential difference across the lamp effectively.
