- An electric field is a region of space in which an electric charge “feels” a force
- The electric field strength at a point is defined as:
The electrostatic force per unit positive charge acting on the charge at that point
- The electric field strength can be calculated using the equation:
- E = electric field strength (N C-1)
- F = electrostatic force on the charge (N)
- Q = charge (C)
- It is important to use a positive test charge in this definition, as this determines the direction of the electric field
- The electric field strength is a vector quantity, it is always directed:
- Away from a positive charge
- Towards a negative charge
- Recall that opposite charges (positive and negative) charges attract each other
- Conversely, like charges (positive and positive or negative and negative) repel each other
A charged particle is in an electric field with electric field strength 3.5 × 104 N C-1 where it experiences a force of 0.3 N.
Calculate the charge of the particle.