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CAIE
18. Electric fields
18.1 Electric fields and field lines
- understand that an electric field is an example of a field of force and define electric field as force per unit positive charge
- recall and use F = qE for the force on a charge in an electric field
- represent an electric field by means of field lines
18.2 Uniform electric fieldsraction
- recall and use E = ∆V/∆d to calculate the field strength of the uniform field between charged parallel plates
- describe the effect of a uniform electric field on the motion of charged particles
18.3 Electric force between point charges
- understand that, for a point outside a spherical conductor, the charge on the sphere may be considered to be a point charge at its centre
- recall and use Coulomb’s law F = Q1 Q2 /(4πε0r 2 ) for the force between two point charges in free space
18.4 Electric field of a point charge
- recall and use E = Q/(4πε0r 2 ) for the electric field strength due to a point charge in free space
18.5 Electric potential
- define electric potential at a point as the work done per unit positive charge in bringing a small test charge from infinity to the point
- recall and use the fact that the electric field at a point is equal to the negative of potential gradient at that point
- use V = Q/(4πε0r) for the electric potential in the field due to a point charge
- understand how the concept of electric potential leads to the electric potential energy of two point charges and use EP = Qq/(4πε0r