Electric Charges and Fields Key Terms (Chapter 5)

Question 1

charging by induction

Answer 1

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

Question 2

conduction electron

Answer 2

electron that is free to move away from its atomic orbit

Question 3

conductor

Answer 3

material that allows electrons to move separately from their atomic orbits; object with properties that allow charges to move about freely within it

Question 4

continuous charge distribution

Answer 4

total source charge composed of so large a number of elementary charges that it must be treated as continuous, rather than discrete

Question 5

coulomb

Answer 5

SI unit of electric charge

Question 6

Coulomb force

Answer 6

another term for the electrostatic force

Question 7

Coulomb’s Law

Answer 7

mathematical equation calculating the electrostatic force vector between two charged particles

Question 8

dipole

Answer 8

two equal and opposite charges that are fixed close to each other

Question 9

dipole moment

Answer 9

property of a dipole; it characterizes the combination of distance between the opposite charges, and the magnitude of the charges

Question 10

electric charge

Answer 10

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 electric force

Question 11

electric field

Answer 11

physical phenomenon created by a charge; it “transmits” a force between two charges

Question 12

electric force

Answer 12

noncontact force observed between electrically charged objects

Question 13

electron

Answer 13

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

Question 14

electrostatic attraction

Answer 14

phenomenon of two objects with opposite charges attracting each other

Question 15

electrostatic force

Answer 15

amount and direction of attraction or repulsion between two charged bodies; the assumption is that the source charges have no acceleration

Question 16

electrostatic repulsion

Answer 16

phenomenon of two objects with like charges repelling each other

Question 17

electrostatics

Answer 17

study of charged objects which are not in motion

Question 18

field line

Answer 18

smooth, usually curved line that indicates the direction of the electric field

Question 19

field line density

Answer 19

number of field lines per square meter passing through an imaginary area; its purpose is to indicate the field strength at different points in space

Question 20

induced dipole

Answer 20

typically an atom, or a spherically symmetric molecule; a dipole created due to opposite forces displacing the positive and negative charges

Question 21

infinite plane

Answer 21

flat sheet in which the dimensions making up the area are much, much greater than its thickness, and also much, much greater than the distance at which the field is to be calculated; its field is constant

Question 22

infinite straight wire

Answer 22

straight wire whose length is much, much greater than either of its other dimensions, and also much, much greater than the distance at which the field is to be calculated

Question 23

insulator

Answer 23

material that holds electrons securely within their atomic orbits

Question 24

ion

Answer 24

atom or molecule with more or fewer electrons than protons

Question 25

law of conservation of charge

Answer 25

net electric charge of a closed system is constant

Question 26

linear charge density

Answer 26

amount of charge in an element of a charge distribution that is essentially one-dimensional (the width and height are much, much smaller than its length); its units are C/m

Question 27

neutron

Answer 27

neutral particle in the nucleus of an atom, with (nearly) the same mass as a proton

Question 28

permanent dipole

Answer 28

typically a molecule; a dipole created by the arrangement of the charged particles from which the dipole is created

Question 29

permittivity of vacuum

Answer 29

also called the permittivity of free space, and constant describing the strength of the electric force in a vacuum

Question 30

polarization

Answer 30

slight shifting of positive and negative charges to opposite sides of an object

Question 31

principle of superposition

Answer 31

useful fact that we can simply add up all of the forces due to charges acting on an object

Question 32

proton

Answer 32

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

Question 33

static electricity

Answer 33

buildup of electric charge on the surface of an object; the arrangement of the charge remains constant (“static”)

Question 34

superposition

Answer 34

concept that states that the net electric field of multiple source charges is the vector sum of the field of each source charge calculated individually

Question 35

surface charge density

Answer 35

amount of charge in an element of a two-dimensional charge distribution (the thickness is small); its units are C/m2

Question 36

volume charge density

Answer 36

amount of charge in an element of a three-dimensional charge distribution; its units are C/m3

Question 37

Coulomb’s law equation

Answer 37

Question 38

Constant k

Answer 38

Question 39

mass of electron

Answer 39

9.109 x 10^-31 kg

Question 40

mass of proton

Answer 40

1.673 x 10^-27 kg

Question 41

mass of neutron

Answer 41

1.675 x 10^-27 kg

Question 42

1 nanometer = 1nm

Answer 42

= 10^-9 m

Question 43

1 micrometer = 1 um

Answer 43

= 10^-6 m

Question 44

1 millimeter = 1mm

Answer 44

= 10^-3 m

Question 45

1 centimeter = 1 cm

Answer 45

= 10^-2 m

Question 46

1 kilometer = 1 km

Answer 46

= 10^3 m