Electrostatics Lecture Notes

Vocabulary practice flashcards covering key definitions, laws, constants, and field concepts in electrostatics.

Electrostatics

The study of electrically charged objects.

Coulomb ($C$)

The standard SI unit used to measure electric charge ($Q$).

Elementary charge ($e$)

The smallest possible charge, having a magnitude of $e = 1,6 \times 10^{-19}\,C$.

Principle of Quantization of Charge

All charges ($Q$) in the universe consist of an integer multiple ($n$) of the elementary charge ($e$), expressed mathematically as $Q = ne$.

Principle of Conservation of Charge

Charge cannot be created or destroyed, only transferred from one object to another. For two identical contact spheres, $Q = \frac{Q_1 + Q_2}{2}$.

Electrostatic force ($F$)

A non-contact force exerted between two charges, which can be either attractive (for unlike charges) or repulsive (for like charges).

Coulomb's Law of Electrostatics

The magnitude of the electrostatic force exerted by two point charges ($q_1$ and $q_2$) on each other is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance ($r$) between them.

Coulomb's constant ($k$)

The proportionality constant in Coulomb's Law, equal to $k = 9 \times 10^9\,N \cdot m^2 \cdot C^{-2}$.

Field

A region in space in which each point is affected by a force.

Electric Field (E-field)

A region in space found around an object with charge, where another charge placed inside it experiences an electrostatic force.

Electric field lines

Imaginary lines representing an electric field that originate perpendicularly from the surface of positive charges, point toward negative charges, never cross, and whose line density indicates field magnitude.

Electric field strength ($E$) at a point

The electrostatic force ($F$) experienced per unit positive charge ($q$) placed at that point, given by $E = \frac{F}{q}$ and measured in $N \cdot C^{-1}$.

Formula for electric field strength due to a point charge ($Q$)

$E = \frac{kQ}{r^2}$, giving the magnitude of the electric field at a distance $r$ away from a source charge $Q$.

Electric field pattern between two negative point charges

A repelling electric field pattern where lines point inward toward both negative charges and bend away from each other without crossing.

Electric field pattern between opposite point charges (dipole)

An attracting electric field pattern where lines originate at the positive charge, curve through space, and terminate at the negative charge.