Glossary
Coulomb's Law
A mathematical expression that quantifies the magnitude of the electrostatic force between two point charges, stating it is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.
Example:
Using Coulomb's Law, you can calculate the strong repulsive force between two protons in an atomic nucleus if you know their charges and separation.
Coulomb's constant (k)
A proportionality constant used in Coulomb's Law, relating the electrostatic force to the magnitudes of charges and the distance between them.
Example:
In a vacuum, the value of Coulomb's constant is approximately , which is essential for calculating electrostatic forces.
Electric Field
A region of space around a charged object where another charged object would experience an electrostatic force. It is represented by field lines indicating the direction of force on a positive test charge.
Example:
The Earth's magnetic field is analogous to an electric field in that it exerts a force on magnetic materials, just as an electric field exerts a force on charges.
Electric Field Strength (E)
A vector quantity representing the force per unit positive test charge at a given point in an electric field, indicating both magnitude and direction.
Example:
If a 2 C charge experiences a 10 N force in an electric field, the electric field strength at that point is 5 N/C.
Electrostatic Force
A fundamental force that governs the interactions between charged particles, causing like charges to repel and opposite charges to attract.
Example:
When you rub a balloon on your hair, the electrostatic force causes your hair to stand on end as it's attracted to the charged balloon.
Field lines
Imaginary lines used to visualize an electric field, originating from positive charges and terminating at negative charges, with their density indicating field strength.
Example:
When drawing the electric field around a dipole, the field lines curve from the positive charge to the negative charge, never crossing.
Point Charges
Idealized charged objects considered to have negligible size, from which electric field lines radiate outward (positive) or inward (negative).
Example:
The electric field around a single electron can be approximated as that of a point charge, with field lines pointing inward.
Source charge
The charge or distribution of charges that creates an electric field in the surrounding space.
Example:
In the formula for the electric field due to a point charge, 'Q' represents the source charge that generates the field.
Test charge
A hypothetical, infinitesimally small positive charge used to determine the direction and magnitude of an electric field at a point without significantly altering the field itself.
Example:
To map out 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 oppositely charged, parallel conducting plates that creates a nearly uniform electric field between them.
Example:
Capacitors often use two parallel plates to store electrical energy, creating a consistent electric field in the space between them.