Defining an Electric Field (Edexcel IAL Physics)

Spec point — 92

Defining an Electric Field

• An electric field is defined as a region of space in which a charged particle experiences a force

  • Hence, electric fields are a type of force field

• The charged particle could be stationary or moving, and will experience an electric force in that field

• All charged particles create their own electric fields

  • These fields exert an electrostatic force, F_E on other charged particles

The electrostatic force between two charges

• Like charges (positive and positive, or negative and negative) repel each other

  • This means the force on each charge are away from the other charge

• Opposite charged (positive and negative) attract each other

  • This means the force on each charge is towards the other charge

• The size of the force changes with distance

A repulsive force decreases with distance

Exam Hint Electric fields are slightly different in that a charged particle will experience a force in this field whether it's stationary or moving. Don't get this mixed up with a magnetic field, where a charged particle only experiences a force if it's moving.