A student is carrying out an investigation into the resistance of a thermistor.
The student:
• puts the thermistor into a beaker containing cold water
• links the thermistor into the circuit diagram shown in Fig. 3.1.
(a(i))[1]
In Fig. 3.1, add a voltmeter so that it measures the voltage $V$ across the thermistor.
(a(ii))[2]
Write down the current $I$ and the voltage $V$ when the thermistor is in cold water.
(b(i))[1]
Explain why the student stirs the water.
(b(ii))[2]
Using $R = \frac{V}{I}$, state how the thermistor's resistance changes as the water gets hotter. Explain how the values shown in Fig. 3.2 and Fig. 3.3 support your response.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Voltmeter shown in the correct position in the circuit and with the right symbol” …