Electric Charges and Fields Flashcards

Vocabulary flashcards for Chapter 1: Electric Charges and Fields.

Electrostatics

The study of forces, fields, and potentials arising from static charges.

Electric Charge

A fundamental property of matter that can be positive or negative and is responsible for electric forces.

Electrified

Acquiring an electric charge on rubbing.

Polarity of Charge

The property that differentiates the two kinds of charges, positive and negative.

Electrically Neutral

Having no net electric charge.

Gold-leaf electroscope

A simple apparatus to detect charge on a body.

Conductors

Substances that readily allow passage of electricity through them.

Insulators

Substances that offer high resistance to the passage of electricity through them.

Point Charges

Charged bodies that are very small compared to the distances between them.

Additivity of Charges

The total charge of a system is obtained simply by adding algebraically all the individual charges.

Conservation of Charge

The total charge of an isolated system is always conserved; no new charges are either created or destroyed.

Quantisation of Charge

All free charges are integral multiples of a basic unit of charge denoted by e.

Coulomb (C)

The SI unit of electric charge.

Coulomb's Law

The magnitude of the force (F) between two point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them.

Permittivity of free space

Denoted by 0, is a constant that quantifies the ability of a vacuum to permit electric fields.

Principle of Superposition

The force on any charge due to a number of other charges is the vector sum of all the forces on that charge due to the other charges, taken one at a time.

Electric Field

The electric force per unit charge experienced by a test charge placed at a point.

Source Charge

The charge which is producing the electric field.

Test Charge

The charge which tests the effect of a source charge.

Electric Field Lines

A way of pictorially mapping the electric field around a configuration of charges; the tangent to it at each point is in the direction of the net field at that point.

Electric Flux

The measure of the number of electric field lines passing through a surface.

Electric Dipole

A pair of equal and opposite point charges q and –q, separated by a distance 2a.

Dipole Moment

A vector whose magnitude is charge q times the separation 2a (between the pair of charges q, –q) and the direction is along the line from –q to q.

Continuous Charge Distribution

A distribution of charge where the charge is spread continuously over a region, rather than being concentrated at discrete points.

Linear Charge Density

Charge per unit length, denoted by λ.

Surface Charge Density

Charge per unit area, denoted by σ.

Volume Charge Density

Charge per unit volume, denoted by ρ.

Gauss's Law

The electric flux through a closed surface S is equal to the total charge enclosed by S divided by the permittivity of free space (ε0).

Gaussian Surface

The surface chosen for the application of Gauss’s law.