Thermistor Questions

Q2.

(a)     A student wishes to investigate how the resistance of a thermistor changes with temperature.

(i)      Draw a labelled diagram of a suitable circuit that would enable the student to measure the resistance of the thermistor.

(2 marks)

(ii)     Describe the procedure the student would follow in order to obtain accurate and reliable measurements of the resistance of the thermistor at different temperatures.

(6 marks)

(b)     The diagram below shows a thermistor connected in series with a resistor, R, and battery of EMF 6.0  V and negligible internal resistance.

When the temperature is 50 °C the resistance of the thermistor is 1.2 kΩ. The voltmeter connected across R reads 1.6V.

(i)      Calculate the pd across the thermistor.

(1 mark)

(ii)     Calculate the current in the circuit.

(1 mark)

(iii)     Calculate the resistance of R quoting your answer to an appropriate number of significant figures.

(2 marks)

(c)     State and explain the effect on the voltmeter reading if the internal resistance of the battery in the circuit in part (b) was not negligible.

(2 marks)

(Total 14 marks)