# To investigate the variation of current ( I ) with pd ( V ) for a metallic conductor.

When a voltage source is connected to the ends of a metallic conductor (a piece of wire) a current flows through the conductor. In this experiment we investigate how the current flowing through the conductor varies with different voltages applied across the conductor.

Procedure:
1. Note that current is 0 when voltage is 0. Record the voltage and current results in a table.

2. Click on the slider to increase the voltage from the potentiometer.

3. Record the voltage and current readings from the voltmeter and ammeter.

4. Repeat steps 2 and 3 until you have at least six sets of readings.

Analysis:
Draw a graph of current (y-axis) against voltage to find the relationship between them. Note: Start both axes at zero.
Draw a "best fit" straight line. A straight line through the origin shows that current is directly proportional to voltage.
The resistance of the wire can be calculated from the graph: R = V / I so resistance = slope. Precautions:

• Use a low voltage so that the current flowing will be small enough that the temperature of the wire stays constant.
• Use a sensitive milliameter and voltmeter to get accurate readings.

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