Electric Fields

What is the Electric Field Strength?

The force per unit charge acting on a positive test charge in an electric field

What is electric potential?

The work done per unit positive charge in moving a charge from infinity to a point r.

What is the electrostatic force?

The force F between 2 charged bodies is directly proportional to the product of their charged and inversely proportional to their separation squared.

If the electrostatic force is positive, how do the 2 charged behave?

They repel

If the electrostatic force is negative, how do the 2 charges behave?

They attract

In what type of field is the electric field strength constant? And what is the formula?

Uniform, E=V/D

In what type of field is the field strength varied? And what is the formula?

Radial, E=Q/4pieR²

What are electric field lines?

The direction a force will act on a charged particle in an electric field.

What is the work done to move a charged particle q from A to B between 2 parallel plated of uniform field?

W = q x (change in) V

Explain the motion of a electron travelling at a constant speed through a vertical field.

The horizontal velocity component is unchanged but there is a vertical acceleration upwards from a constant force. Causing the electron to follow a parabolic path towards the positive plate.

How does potential change with increasing distance?

It decreases

How does potential change signs?

If the charge is positive, the potential is positive and the force of charge is repulsive. Vice versa for negative charge.

For a graph of Potential against distance, what does the gradient show?

The electric field strength at any point in that field

How much work is done to move across an equipotential surface?

none

What do the equipotential lines look like in a uniform field?

straight lines parallel to the plates

What do the equipotential lines look line in a radial field?

concentric circles which get further apart with increasing distance

For a graph of electric field strength against distance, what does the area under the graph represent?

The electric potential DIFFERENCE

How does the charge affect the parabolic shape of a charged particle in motion through a uniform field?

The greater the charge, the greater the deflection

How does the mass affect the parabolic shape of a charged particle in motion through a uniform field?

Increasing mass, decreases the amount of deflection it experiences

How does the speed affect the parabolic shape of a charged particle in motion through a uniform field?

Increasing speed decreases the deflection

What type of quantity is Electric field strength?

Vector

How does electric potential change with increasing distance from a negative charge?

It increases

In the work done equation, what does the q represent?

The charge that is being moved in the potential produced by Q.