Electric Fields

• Electric field


  A field created around any electrically charged object
• Electric field


  • The closer to the object you get, the stronger the field is
  • The further you are from it, the weaker it is
• Showing an electric field around an object

  1. Draw field lines

  2. Field lines go from positive to negative

  3. Field lines are at a right angle to the surface

  4. The closer together the lines are, the stronger the field is

  5. The further from a charge you go, the further apart the lines are and so the weaker the field is
• Charged object in an electric field

  Feels a force
• As you increase the distance between charged objects

  The strength of the field decreases and the force between them gets smaller
• Interaction between electric fields of two oppositely charged particles


  1. The electric field of Q interacts with the electric field of q

  2. This causes forces to act on both Q and q

  3. These forces move q and Q closer together
• Sparks are caused when there is a high enough potential difference between a charged object and the earth (or an earthed object)
• High potential difference


  Causes a strong electric field between the charged object and the earthed object
• Sparking


  1. The strong electric field causes electrons in the air particles to be removed (known as ionisation)

  2. Air is normally an insulator, but when it is ionised it is much more conductive, so a current can flow through it