Practical electricity experiment questions
Q1.
(a) A student is given a piece of metal wire and asked to investigate how the resistance of the wire changes between a temperature of 0 oC and 100 oC.
(i) Draw a labelled diagram of a suitable arrangement that would enable the student to carry out the experiment.
circuit with ammeter in series with the wire and a voltmeter in parallel with it ![](../../../../graphics/symbols/nuclides/ticksmall.png)
some means of heating the wire (eg water bath) ![](../../../../graphics/symbols/nuclides/ticksmall.png)
thermometer immersed in the water bath ![](../../../../graphics/symbols/nuclides/ticksmall.png)
(3 marks)
(ii) Describe the procedure the student would follow in order to obtain accurate and reliable measurements of the resistance of the wire at different temperatures. The temperature range should be between 0 oC and 100 oC.
- water bath method used - wire encased in insulator (plastic bag) and immersed in a beaker of water.
- ice added to water until it reaches zero degrees.
- water stirred
- and the temperature measured with thermometer
- switch closed on the circuit
- current and p.d. noted down
- resistance calculated as V/I
- bunsen used (or electrical heater used) to raise the temperature ten degrees then to point 3 on this method list again until water is 100 degrees Celsius.
- Graph drawn of Resistance (y-axis) against temperature (x-axis)
(6 marks)
(b) A certain metal has a critical temperature of –268 oC (5 K). Explain what is meant by critical temperature.
The critical temperature is the temperature at or below which
a material becomes a superconductor i.e. has zero resistance or resistivity.![](../../../../graphics/symbols/nuclides/ticksmall.png)
(2 marks)
(Total 11 marks)