potential difference

• what is potential difference?


  the work done per unit charge when it moves between two points in a circuit
• how does potential difference work?


  a build up off charge causes a buildup of energy

  we call this electrical potential or just 'potential'

  potential is the energy available per unit charge at a point in a circuit

  potential is measured in volts (V)

  potential can also be measured in joules per coulomb (J/C)
• potential difference through a van de graaf


  1 - switch on the van de graaf

  2 - charge builds up on the insulating belt

  3 - energy builds on the metal dome of the generator

  4 - the potential difference on the dome increases

  5 - the second metal sphere is earthed and has a potential difference of 0v

  6 - once a spark is discharged, there is now a potential difference between the dome and sphere

  7 - the potential difference causes a spark from the van de graaf to the sphere when it is big enough
• potential difference equation


  V = E/Q

  V = voltage

  E = potential difference

  Q = charge