CIE IGCSE Physics

Revision Notes

4.2.7 Potential Difference

What is Potential Difference?

  • As charge flows around a circuit, energy is transferred to or from the charge
  • The potential difference (voltage) between two points in a circuit is related to the amount of energy transferred between those points in the circuit
  • Potential difference is measure in volts (V)

Potential difference, IGCSE & GCSE Physics revision notes

The potential difference is the voltage across each component: 5 volts for the bulb (on the left) and 7 volts for the resistor (on the right)

 

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Potential Difference & Energy

  • The potential difference between two points in a circuit is the amount of energy transferred by each unit of charge passing between those two points
  • The unit of voltage, the volt (V), is the same as a joule per coulomb (J/C)
1 V = 1 J/C
  • So, for example:
    • If a bulb has a voltage of 3 V, every coulomb of charge passing through the bulb will lose 3 J of energy

 

Exam Tip

Think of potential difference as being the energy per coulomb.

 

 

Measuring Potential Difference

  • Potential difference can be measured using a voltmeter
  • The voltmeter should be connected in parallel with the part of the circuits you want to measure the potential difference of

Measuring potential difference voltmeter, IGCSE & GCSE Physics revision notes

Potential difference can be measured by connecting a voltmeter between two points in a circuit

 

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