Glossary
Average electric field
The average electric field between two points is the electric potential difference divided by the distance between them, indicating the strength and direction of the field.
Example:
If you measure a 12V potential difference across two parallel plates separated by 0.1m, you can calculate the average electric field between them to be 120 V/m.
Electric field vectors
Electric field vectors are arrows used to represent the direction and magnitude of the electric field at various points in space, indicating the force a positive test charge would experience.
Example:
Around a positive point charge, the electric field vectors would all point radially outward, showing that a positive test charge would be repelled away from it.
Electric potential
Electric potential is the electric potential energy per unit charge at a point in space, indicating how much potential energy a positive charge would have if placed there.
Example:
When you lift a book, you increase its gravitational potential; similarly, moving a positive charge to a point of higher electric potential increases its electrical potential energy.
Electric potential difference
Electric potential difference is the change in electric potential energy per unit charge when a test charge moves between two points in an electric field.
Example:
When a lightning bolt strikes, there's a massive electric potential difference between the cloud and the ground, causing a huge flow of charge.
Equipotential lines
Equipotential lines are imaginary lines or surfaces that connect points in an electric field where the electric potential is equal.
Example:
On a topographical map, contour lines show points of equal elevation; similarly, equipotential lines on an electric field map show points of equal electric 'height.'
Scalar superposition
Scalar superposition is the principle that the total electric potential at a point due to multiple point charges is the algebraic sum of the individual potentials created by each charge.
Example:
To find the total potential at a point near two charges, you simply add the potential from the first charge to the potential from the second charge using scalar superposition, without worrying about their directions.
Voltage
Voltage is the common term for electric potential difference, representing the 'push' or electromotive force that drives electric current in a circuit.
Example:
Plugging your phone into a wall outlet provides the necessary voltage to charge its battery, pushing electrons through the charging circuit.
Volts (V)
Volts are the SI unit of electric potential and electric potential difference, representing one joule of energy per coulomb of charge.
Example:
A standard AA battery provides 1.5 volts (V), meaning it can supply 1.5 joules of energy for every coulomb of charge that flows through it.