Plan an experiment to investigate how the thickness of a metal wire affects its resistance. The resistance of a wire can be found using the equation: resistance of wire = potential difference (p.d.) across wire / current in the wire The following apparatus is available: • six lengths of metal wire, each of different thickness • an ammeter • a voltmeter • a power supply • several connecting leads • a micrometer. Other apparatus normally available in a school laboratory can also be used. You are not required to do this experiment. In your plan, you should: • draw a circuit diagram to show how you will use the apparatus • explain briefly how to carry out the investigation • state the key variables to keep constant • draw a table, with column headings, to show how to display readings (you are not required to enter any readings in the table) • explain how to use these readings to reach a conclusion.

1. Draw a circuit diagram to show how you will use the apparatus Explain briefly how to carry out the investigation State the key variables to keep constant Draw a table, with column headings, to show how to display readings (you are not required to enter any readings in the table) Explain how to use these readings to reach a conclusion.[6]