Concept Map

Concept Trailer: Electric potential

Concept Trailer: Electric fields

Key Terms

chapter 18

conductor

a material that allows electrons to move separately from their atomic orbits

conductor

an object with properties that allow charges to move about freely within it

Coulomb force

another term for the electrostatic force

Coulomb interaction

the interaction between two charged particles generated by the Coulomb forces they exert on one another

Coulomb’s law

the mathematical equation calculating the electrostatic force vector between two charged particles

electric charge

a physical property of an object that causes it to be attracted toward or repelled from another charged object; each charged object generates and is influenced by a force called an electromagnetic force

electric field

a three-dimensional map of the electric force extended out into space from a point charge

electric field lines

a series of lines drawn from a point charge representing the magnitude and direction of force exerted by that charge

electromagnetic force

one of the four fundamental forces of nature; the electromagnetic force consists of static electricity, moving electricity and magnetism

electron

a particle orbiting the nucleus of an atom and carrying the smallest unit of negative charge

electrostatic equilibrium

an electrostatically balanced state in which all free electrical charges have stopped moving about

electrostatic force

the amount and direction of attraction or repulsion between two charged bodies

electrostatic repulsion

the phenomenon of two objects with like charges repelling each other

electrostatics

the study of electric forces that are static or slow-moving

Faraday cage

a metal shield which prevents electric charge from penetrating its surface

field

a map of the amount and direction of a force acting on other objects, extending out into space

free charge

an electrical charge (either positive or negative) which can move about separately from its base molecule

free electron

an electron that is free to move away from its atomic orbit

induction

the process by which an electrically charged object brought near a neutral object creates a charge in that object

insulator

a material that holds electrons securely within their atomic orbits

law of conservation of charge

states that whenever a charge is created, an equal amount of charge with the opposite sign is created simultaneously

proton

a particle in the nucleus of an atom and carrying a positive charge equal in magnitude and opposite in sign to the amount of negative charge carried by an electron

screening

the dilution or blocking of an electrostatic force on a charged object by the presence of other charges nearby

static electricity

a buildup of electric charge on the surface of an object

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capacitance

amount of charge stored per unit volt

capacitor

a device that stores electric charge

defibrillator

a machine used to provide an electrical shock to a heart attack victim’s heart in order to restore the heart’s normal rhythmic pattern

dielectric

an insulating material

dielectric strength

the maximum electric field above which an insulating material begins to break down and conduct

electric potential

potential energy per unit charge

electron volt

the energy given to a fundamental charge accelerated through a potential difference of one volt

equipotential line

a line along which the electric potential is constant

grounding

fixing a conductor at zero volts by connecting it to the earth or ground

mechanical energy

sum of the kinetic energy and potential energy of a system; this sum is a constant

parallel plate capacitor

two identical conducting plates separated by a distance

polar molecule

a molecule with inherent separation of charge

potential difference (or voltage)

change in potential energy of a charge moved from one point to another, divided by the charge; units of potential difference are joules per coulomb, known as volt

scalar

physical quantity with magnitude but no direction

vector

physical quantity with both magnitude and direction