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 results in a table as shown below
  2. Click on the right hand side of the slider at the top 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 seven sets of readings
  5. Set the slider to the left (zero)
  6. To repeat the experiment click on the "Increase supply voltage" button to get a new supply voltage and follow steps 2 to 4 to get another set of readings
Voltage (V)
Current (A)
   

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.

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