Electric Fields

An electric field is a region of space where charges experience forces.

A point charge or a uniformly charged sphere produces a radial field. Oppositely charged parallel plates produce a uniform field.
We cannot see electric fields but we can represent them with electric field lines on a diagram.

The direction of the field is the direction of the force that would act on a small positive charge.

Electric field strength has the symbol E and is measured in N / C or V / m

Electric field strength is the force that would act on unit charge, i.e. 1 coulomb so E = F / Q

Questions 1,2,3

Coulombs Law

Two point charges exert a force on each other that is proportional to the product of their charges and inversely proportional to the square of their separation.

Questions 4, 5, 6

So now we can derive an expression for the field strength in a non uniform field.

Question 7