Ohm’s Law and Resistance
Resistance is a measure of how difficult it is for electricity to flow
through a part of a circuit. It is measured in units called ohms
which has the symbol .
Resistance cannot be measured directly but can be calculated
after measuring voltage and current. To calculate resistance we
need to use Ohm’s Law.
Ohm’s Law is summarised into the following equation:
V
R
I
Where R = resistance in ohms
V = voltage in volts and
I = current in amperes
 practical TASK:

Start with the voltage in your powerpack at 2V and measure the voltage and current as shown

Next turn it up to 4V and measure again – continue until 10 V

Use Ohm’s Law to calculate the resistance of your resistor for each pair of voltage and current values.
Voltage (V)

Current (I)
Resistance ()
Comment on your resistance values.
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