ZIMSEC O Level Combined Science Notes:  Experiment: Finding the resistance of a resistor using a voltmeter

Aim:  To find the resistance of a resistor in a circuit using voltmeter

Materials: cells, ammeter, resistor,switch, leads with crocodile clips

Finding Resistance


  1. Set up the circuit as shown above
  2. Close the switch
  3. Read and record values of the ammeter and voltmeter measurements
  4. Repeat steps 2 and 3 with two, then three then four cells respectively
  5. Use Ohm’s Law to find the resistance of the resistor
  6. Use Ohm’s law to find resistance

Results and Observations

  • Current increases proportionally with an increase in voltage


  • For example if the current is 2 Amps and the 6 Volts
  • Then the resistance is 3 Ohms
  • This is found by the formula
  • R=\dfrac{V}{I}

To access more topics go to the Combined Science Notes page.