Physics Unit 7

Ch. 15 & Ch. 16

electric field (E)

A region of space that would produce an electric force on any other charged object.

Lines of Force

Illustrative lines that show the direction of the electric force that a charged object exerts on a small positive charge.

Electric Field Strength

The magnitude of the electric field in force per unit of charge.

test charge

A positive charge that is small enough that its electric field has a negligible effect on the field it is testing.

electric potential energy (Ue)

A measure of the amount of mechanical work necessary to move a charge from zero potential energy to a defined position near a point charge.

electric potential (V)

The work per unit charge necessary to move a charge from a location of zero potential energy to a position near a point charge.

potential difference (ΔV)

The difference in electric potential between any two positions in an electric field, equal to the work necessary to move a unit charge between those positions.

Equipotential Surfaces

Theoretical surfaces where each point has equal electric potential; no work is done when moving a test charge along these surfaces.

capacitor

an electrical device that stores charge consisting of two conductors seperated by a vauum

dielectric

the vacuum that separates the plates of a capacitor

capacitance

the amount of charge that can be stored per unit of potential difference in a capacitor

ɛ

the permittivity of free space

permittivity of material

a measure of how easily an electric field can permeate a material

static electricity

an imbalance of charge within an object

law of charges

the law stating that unlike charges attract and like charges repel

electrical conductor

a material with loosely held charges that can easily move through it

electrical insulator

a material with tightly held charges that prevents charges from easily moving though it

semiconductor

a material with variable conductivity that can be controlled by conditions such as impurities, temperature, or electric fields

electrical ground

a conductive body so large that its charge is relatively unaffected when electrons are added or removed

electrostatic force (F_e)

the attractive or repulse force between any two charged objects

k

coulomb’s constant, equal to 8.99 ∙ 10⁹