Ch. 20

Question 1

how are charges and electric fields related

Answer 1

charges create an electric field

Question 2

when is an object neutral

Answer 2

when it has equal amounts of positive and negative charges

Question 3

when does an object become negatively charged

Answer 3

when the amount of negative charge on it exceeds the amount of positive charge

Question 4

when does an object become positively charged

Answer 4

when it has more positive charge than negative charge

Question 5

what type of force is the force between two particles

Answer 5

they are action-reaction pair that are equal in magnitude and opposite in direction

Question 6

if you increase the distance between two objects what happens?

Answer 6

the force decreases (inversely proportional to the square of the distance)

Question 7

if you decrease the charge on two objects what happens to the force between them

Answer 7

it decreases

Question 8

what do we use coulomb’s law for

Answer 8

we use it to calculate the force between two charged objects

Question 9

what is charge an inherent property of?

Answer 9

electrons and protons

Question 10

a neutral macroscopic object has how many protons and electrons

Answer 10

the same

Question 11

how are protons and electrons similar

Answer 11

they have the same exact (opposite) charge despite the electron being less massive

Question 12

how do objects gain a positive charge

Answer 12

by losing electrons (valency)

Question 13

what is ionization

Answer 13

it is the process of removing an electron from the electron cloud of an atom to produce a positive ion

Question 14

what is an insulator

Answer 14

electrons are tightly bound to the positive nuclei within and are not free to move around, electric charge cannot pass through

Question 15

what is a conductor

Answer 15

In metals, the outer electrons (valence) are weakly bound and can detach from their parent ion and can move through the solid

Question 16

what is an electric dipole

Answer 16

an electric dipole is equal but opposite charges with a separation between them

Question 17

what is the field model

Answer 17

it explains how the force due to charges is transmitted through empty space

Question 18

when Charge B experiences a force from charge A, what is actually the agent?

Answer 18

the alteration of space around a charge is the agent that exerts a force on charge B

Question 19

which way does an electric force point on a positive charge?

Answer 19

it points away from it. . For example, if a positive source charge generates an electric field that points away from it, then a positive test charge placed in the field will feel a force in the same direction, away from the source charge.

Question 20

which way does an electric field force vector point on a negative charge

Answer 20

it points towards it, a positive charge placed in the electric field of a negative charge would feel a force vector towards the negative charge

Question 21

how do you draw an electric field vector?

Answer 21

you draw it tangent to the electric field line

Question 22

where is an electric field stronger?

Answer 22

it is stronger where the electric field vectors are longer and closer together

Question 23

the electric field at any point is the

Answer 23

vector addition of the individual fields

Question 24

what are the rules for drawing electric field lines

Answer 24

draw the field lines starting on the positive charges and moving toward the negative charges

make the lines close together where the field is stronger

Question 25

what is true of the electric field in a parallel plate capacitor

Answer 25

the electric field at every point is the same in strength and direction (this is the uniform electric field)

Question 26

what does the electric field in a parallel play capacitor depend on?

Answer 26

It depends on the charge and area of the plates

Question 27

what does it mean when a conductor is in electrostatic equilibrium

Answer 27

no charges are moving

Question 28

when a conductor is in electrostatic equilibirum, what is true about the electric field?

Answer 28

it is zero

Question 29

what happens to the excess charge in a conductor at estatic equilibrium?

Answer 29

the charge moves to the surface and the electric field is perpendicular to the surface

Question 30

where is the electric field stronger in a conductor?

Answer 30

at sharp points the density of the charge is higher

Question 31

If you place a charged object next to an uncharged object that is a conductor,

Answer 31

There is an attractive force between the two objects.

Question 32

A negatively charged rod is brought near a neutral metal sphere. Which of the following is true?

Answer 32

There is an attractive force between the rod and sphere.

Question 33

A neutral object __________.

Answer 33

has no net charge

Question 34

According to Coulomb's law, when the distance between two point charges doubles, what happens to the electric force acting between the charges?

Answer 34

It goes down by a factor of 4.

Question 35

Electric fields exist ____________.

Answer 35

at all points in space around charges

Question 36

The clothes are charged by ______ in the drier. Your body is neutral but the clothes can ______ you a little and attract the opposite charge in your body.

Answer 36

rubbing; polarize

Question 37

is glass and plastic a conductor or insulator

Answer 37

it is a insulator

Question 38

is metal a conductor or insulator

Answer 38

it is a conductor

Question 39

can insulators and conductors be charged?

Answer 39

yes they can be charged but they differ in their abiltiies to move

Question 40

is the force between a charged object and a neutral object attractive or repulsive?

Answer 40

it is attractive due to polarization

Question 41

if an object is charged, what is true about the electrons and protons

Answer 41

there is a difference between them

Question 42

if you rub silk, saran wrap, or polyester on glass, what happens to the charge on the glass?

Answer 42

glass tends to lose electrons so it becomes positive while the silk, wrap, or polyester gains those electrons

Question 43

if you rub a PVC or rubber rod on wool, hair, or nylon, what happens to the charge on the rod?

Answer 43

PVC tends to gain electrons so it will become negative while the other materials become positive

Question 44

what is grounding

Answer 44

it is the ability to absorb positive or negative charges

Question 45

what direction does the electric force on a negative charge point if the electric field is down?

Answer 45

if the electric field is down, the force acting on the charge is opposite so it is pointing up