Page 745 - SUBSEC October 2017_Neat

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6. Using the oscilloscope, adjust the output of the ac supply to a peak voltage of 30V.
7. Switch off the ac supply and connect its output to the 20Ω resistance heating element.
8. Record the initial temperature, Ti, of the water as indicated by the thermometer
9. Switch on the ac supply and start the timer.
10. Stir the water as continuously as is convenient and after 15 minutes (time interval Δt)
switch off the ac supply and record the temperature.
11. Wait for the apparatus to cool.
12. Repeat steps (1) – (10) for a fresh quantity of water (mass of added water, m, should be
the same throughout the experiment) and ac supply of 25V, 20V, 15V and 10V peak
voltages.

TABLE 1: RESULTS OF EXPERIMENT
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Mass of calorimeter
Mass of calorimeter + water
Mass of added water, m
Resistance of heating resistor, R
Time interval, Δt

[3 marks]

(b) Using a suitable table, record the remainder of the results of the experiment in the space
provided below. [4 marks]

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