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1 Record the mass of the aluminium block. Fit a low-voltage heater into an insulated block, and connect the heater into the circuit as shown in Figure 1. Before switching on, measure the initial temperature of the block.
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2 During the time the heater is on, use the variable resistor to keep the current constant. Use the ammeter and the voltmeter to measure the current through and the p.d. across the heater.
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3 Measure the temperature of the block at regular intervals for a fixed time (e.g. 10 minutes) while a constant current is passed through the heater, and for at least half that time again after the heater has been switched off.
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4 Record all your readings.
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5 Repeat the measurements using the steel block.
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6 Estimate the uncertainty in the measurements of the current, the p.d. and the temperature rise.
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1 Record the mass of the aluminium block. Fit a low-voltage heater into an insulated block, and connect the heater into the circuit as shown in Figure 1. Before switching on, measure the initial temperature of the block.
•
2 During the time the heater is on, use the variable resistor to keep the current constant. Use the ammeter and the voltmeter to measure the current through and the p.d. across the heater.
•
3 Measure the temperature of the block at regular intervals for a fixed time (e.g. 10 minutes) while a constant current is passed through the heater, and for at least half that time again after the heater has been switched off.
•
4 Record all your readings.
•
5 Repeat the measurements using the steel block.
•
6 Estimate the uncertainty in the measurements of the current, the p.d. and the temperature rise.