A student investigates the resistance of a thermistor at different temperatures - OCR Gateway - GCSE Physics - Question 20 - 2023 - Paper 1
Question 20
A student investigates the resistance of a thermistor at different temperatures.
The student uses a Bunsen burner to heat the water in a beaker to three different t... show full transcript
Worked Solution & Example Answer:A student investigates the resistance of a thermistor at different temperatures - OCR Gateway - GCSE Physics - Question 20 - 2023 - Paper 1
Step 1
Describe the trend shown by the graph.
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Answer
The graph shows that as the temperature increases, the resistance of the thermistor decreases. This inverse relationship indicates that the thermistor becomes more conductive at higher temperatures.
Step 2
Suggest how the student's method could be improved, include ideas about accuracy and precision.
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Answer
To improve the method, the student could ensure that the temperature increments are consistent and take multiple readings at each temperature to reduce random errors. Additionally, using a more precise thermometer and allowing sufficient time for the thermistor to stabilize at each temperature before taking the reading would enhance accuracy.
Step 3
Which ammeter should the student use to measure a current of 300 mA?
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The student should use Ammeter C, which is rated for 500 mA. This allows enough range to accurately measure the 300 mA current without exceeding the ammeter's capacity.
Step 4
Explain your answer.
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Answer
Ammeter C is the best choice since it is rated higher than 300 mA, ensuring that the measurement stays within the safe operating range. Using an ammeter that is too close to the maximum could lead to damage or inaccurate readings.
Step 5
State one use for a light dependent resistor and describe how it is used.
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One use for a light dependent resistor (LDR) is in automatic night lights. The LDR detects the level of ambient light; as it gets darker (at night), the resistance of the LDR increases, triggering a circuit that turns on the light.
