Glossary
Electric Field Lines
Imaginary lines used to visualize the direction and relative strength of an electric field. They originate from positive charges and terminate on negative charges.
Example:
Around a positive point charge, electric field lines radiate outwards, showing the path a positive test charge would follow if released.
Electric Potential (V)
The potential energy per unit positive charge at a specific point in an electric field, measured in volts (V). It is a scalar quantity.
Example:
If a point in space has an electric potential of 100 V, it means that 100 Joules of potential energy would be associated with every coulomb of positive charge placed there.
Electric Potential Energy (U or W)
The energy a charged particle possesses due to its position within an electric field. It is a form of stored energy that can be converted to kinetic energy.
Example:
A positive charge placed near another positive charge will have high electric potential energy due to the repulsive force, similar to a compressed spring.
Equipotential Lines
Lines in an electric field that connect all points having the same electric potential. They are always perpendicular to electric field lines.
Example:
Around a charged sphere, the concentric circles represent equipotential lines, indicating that any point on a given circle has the same electric potential.
Isolines
Lines that connect points of equal value in a scalar field, used to represent physical quantities like elevation or pressure.
Example:
On a topographical map, isolines connect points of the same elevation, showing the shape of the terrain.
Non-uniform Field
An electric field where the field strength or direction varies from point to point within a region.
Example:
The electric field surrounding a single point charge is a non-uniform field, with field lines radiating outwards and equipotential lines becoming more spread out further from the charge.
Perpendicularity
The property that equipotential lines are always at right angles (90 degrees) to electric field lines, indicating that no work is done moving a charge along an equipotential line.
Example:
When sketching the electric field around a dipole, you must ensure the perpendicularity of the electric field lines to the equipotential lines at every intersection.
Scalar Quantity
A physical quantity that is fully described by its magnitude alone, without requiring a direction.
Example:
Temperature is a scalar quantity; it only has a value (e.g., 20°C) and no associated direction, just like electric potential.
Uniform Field
An electric field where the field strength and direction are constant throughout a given region.
Example:
Between two large, parallel, oppositely charged plates, the electric field is approximately a uniform field, characterized by parallel and evenly spaced equipotential lines.
Voltage (ΔV)
The difference in electric potential between two points in an electric field, also known as potential difference. It represents the work done per unit charge to move a charge between those points.
Example:
A standard car battery provides a voltage of 12 V, indicating a 12 Joule difference in potential energy for every coulomb of charge moved between its terminals.
Work (W)
The energy transferred when a force causes displacement. In the context of electric fields, it is the energy required or released when moving a charge.
Example:
To move a positive charge from a lower potential to a higher potential, an external force must do positive work on the charge, increasing its electric potential energy.