Glossary
Coulomb's Constant (k)
A proportionality constant used in Coulomb's Law and electric field calculations, relating the force between charges to their magnitudes and separation distance.
Example:
When calculating the force between two charged particles, you'll always use Coulomb's constant in the formula.
Electric Field
An electric field is a vector field that describes the force a charged particle would experience at any point in space, acting as an invisible force field surrounding every charged object.
Example:
When you rub a balloon on your hair, you create an electric field around the balloon that can attract small pieces of paper.
Electric Field Lines
Visual representations used to show the direction and strength of an electric field; lines point away from positive charges and towards negative charges, with density indicating strength.
Example:
Observing the electric field lines around a charged comb helps visualize how it attracts uncharged hair strands.
Electric Field Strength (E)
A quantitative measure of the electric force experienced by a charged particle at a specific point in space, represented by 'E' and measured in volts per meter (V/m).
Example:
If a strong lightning bolt creates a powerful electric field, the electric field strength near the ground would be extremely high.
Electric Potential (V)
The amount of electric potential energy per unit charge at a given point in an electric field, often referred to as voltage, measured in volts (V).
Example:
A battery creates an electric potential difference between its terminals, driving current through a circuit.
Electrostatic Force (Fe)
The attractive or repulsive force between any two charged objects, described by Coulomb's Law, which is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.
Example:
The reason your hair stands on end after rubbing a balloon is due to the electrostatic force between your hair and the charged balloon.
Energy
The capacity to do work, which in the context of electric fields can refer to electric potential energy stored by charges in a field or kinetic energy gained by charges moving through a potential difference.
Example:
When an electron accelerates through an electric field, its potential energy is converted into kinetic energy.
Negative Charges
Electric charges that create electric field lines pointing towards them, indicating the direction a positive test charge would move.
Example:
An electron, as a negative charge, draws electric field lines inwards, towards itself.
Point Charges
Idealized electric charges concentrated at a single point in space, whose electric fields radiate outwards or inwards symmetrically.
Example:
The electric field around a single electron can be modeled as if it were a point charge.
Positive Charges
Electric charges that create electric field lines pointing away from them, indicating the direction a positive test charge would move.
Example:
A proton, being a positive charge, generates an electric field that radiates outwards from its center.
Source Charge (Q)
The electric charge that creates an electric field in the surrounding space.
Example:
In a simple circuit, the battery acts as the source charge driving the flow of electrons.
Test Charge (q)
A hypothetical, infinitesimally small positive charge used to determine the direction and magnitude of an electric field at a given point without significantly altering the field itself.
Example:
To map an unknown electric field, physicists imagine placing a tiny test charge at various points and observing the force it experiences.
Two Parallel Plates
A configuration of two conductive plates placed parallel to each other, typically with opposite charges, creating a uniform electric field between them.
Example:
Capacitors often use two parallel plates to store electric charge and create a consistent electric field.
Uniform Electric Field
An electric field where the field strength and direction are constant at every point within a specific region, typically found between two oppositely charged parallel plates.
Example:
Inside a well-designed capacitor, the electric field is nearly a uniform electric field, making calculations simpler.
Vector Field
A field that assigns a vector (magnitude and direction) to each point in space, such as an electric field or gravitational field.
Example:
Wind patterns across a map can be represented as a vector field, showing both wind speed and direction at various locations.