electric fields

• electric field strength is force per unit charge experienced by an object in a field
• a field line is the path taken by a positive test charge
• electric potential is the electric potential energy per unit charge
• equipotential lines are at right angles to field lines
• the area under an electric field strength - distance graph is the electric potential difference
• electric potential energy is the work done to move a positive test charge from infinity to its current position
• electric field strength is also represented by the potential gradient
• electric potential is taken to be 0 at infinity so a positive charge would gain potential as it moves away from the negative charge at infinity
• particles have a parabolic path when entering a charged field
• potential is negative for a negative charge as the charge is attracting to the direction of the field lines
• potential is positive for a positive charge as the charge is repelling from the direction of the field lines
• work is done by the system to travel down a potential gradient
• work is done on the system to travel up a potential gradient