Chapter 22: Electrostatics

Question 1

Which force binds atoms together to form molecules?

Answer 1

electrical

Question 2

In an electrically neutral atom the number of protons in the nucleus is equal to the number of

Answer 2

electrons that surround the nucleus.

Question 3

Strip electrons from an atom and the atom becomes a

Answer 3

positive ion.

Question 4

The unit of electric charge, the coulomb, is the charge on

Answer 4

a specific large number of electrons.

Question 5

A transistor is an example of a

Answer 5

semiconductor.

Question 6

Induction is when

Answer 6

you bring a charged object near another object and cause a movement of charge.

Question 7

Paper plates don’t heat in a microwave because

Answer 7

paper contains no polar molecules.

Question 8

The force between two charged particles depends

Answer 8

on the amount of charge on the two particles and their distance from each other.

Question 9

When a material has no electrical resistance it is

Answer 9

a superconductor.

Question 10

A volt is defined as

Answer 10

a joule per coulomb.

Question 11

General term for electrical phenomena

Answer 11

Electricity

Question 12

The study of electric charge at rest (def)?

Answer 12

Electrostatics

Question 13

Electric charge is neither created nor destroyed. The total charge before an interaction equals the total charge after (def)?

Answer 13

Conservation of charge

Question 14

The relationship between electrical force, charge, and distance (def)?

Answer 14

Coulomb’s law

F = k(q1*q2/d^2)

Question 15

In regard to Coulomb’s law, if the charges are alike in sign, the force is

Answer 15

repulsive.

Question 16

In regard to Coulomb’s law, if the charges are unlike (opposite), the force is

Answer 16

attractive.

Question 17

The SI unit of electrical charge?

Answer 17

Coulomb

Question 18

One coulomb (symbol C) is equal to

Answer 18

the total charge of 6.25 x 10^18 electrons.

Question 19

Any material having free shared particles that easily flow through it when an electric force acts on them?

Answer 19

Conductor

Question 20

A material without free charged particles and through which charge does not easily flow?

Answer 20

Insulator

Question 21

A material with properties that fall between a conductor and an insulator and whose resistance can be affected by adding impurities?

Answer 21

Semiconductor

Question 22

A material that is a perfect conductor with zero resistance to the flow of electric charge?

Answer 22

Superconductor

Question 23

Transfer of electric charge between objects by rubbing or simple touching?

Answer 23

Charging by contact

Question 24

Redistribution of electric charges in and on objects caused by the electrical influence of a charged object close by but not in contact?

Answer 24

Charging by induction

Question 25

Term applied to an atom or molecule in which the charges are aligned so that one side has a slight excess of positive charge and the other side a slight excess of negative charge?

Answer 25

Electrically polarized One side of the atom or molecule is induced into becoming more negative or positive than the opposite side.

Question 26

Defined as electric force per unit charge, it can be considered to be an “aura” surrounding charged objects and is a storehouse of electric energy?

Answer 26

Electric field; Electric field = F/q About a charged point, the field decreases with distance according to the inverse-square law, like a gravitational field. Between oppositely charged parallel plates, the electric field is uniform.

Question 27

The energy a charged object possesses by virtue of its location in an electric field?

Answer 27

Electric potential energy

Question 28

The ______ ________ energy per unit of charge, measured in volts, and often called voltage?

Answer 28

electric potential Voltage = electric potential energy / charge or V=E/q

Question 29

An electrical device--in its simplest form, a pair of parallel conducting plates separated by a small distance--that stores electric charge and energy?

Answer 29

Capacitor Capacitor plates have equal and opposite charges.

Question 30

According to Coulomb’s law, a pair of particles that are placed twice as far apart will experience forces that are: a) half as strong; b) one-quarter as strong; c) twice as strong; d) four times as strong.

Answer 30

b) one-quarter as strong

Question 31

Are gravitational forces attractive or reflective?

Answer 31

Gravitational forces are only attractive.

Question 32

Every atom is composed of

Answer 32

a positively charged nucleus surrounded by negatively charged electrons.

Question 33

Each of the electrons in any atom has

Answer 33

the same quantity of negative charge and the same mass.

Question 34

Protons and neutrons compose the ​

Answer 34

nucleus.

Question 35

Protons are about 1800 times more massive than ________, but each one carries an amount of positive charge equal to the negative charge of electrons.

Answer 35

electrons

Question 36

Neutrons have slightly more mass than _______ and have no net charge.

Answer 36

protons

Question 37

Atoms usually have as many electrons as protons, so the atom has _____ ___ charge.​

Answer 37

zero net

Question 38

When rubbing a comb through your hair, _______ transfer from your hair to the comb. ​ ​ ​

Answer 38

electrons; Your hair has a deficiency of electrons (positively charged).​

Question 39

When rubbing a glass rod with silk, electrons transfer from the rod onto the silk and the rod becomes

Answer 39

positively charged.

Question 40

Metals such as copper and aluminum​ are considered to be

Answer 40

conductors.

Question 41

Materials such as rubber and glass​ are considered to be

Answer 41

insulators.

Question 42

Materials that fall in the middle range of electrical resistivity between insulators and conductors?​

Answer 42

Semiconductors; They are insulators when they are in their pure state.​ They are conductors when they have impurities.​ Semiconductors conduct when light shines on it.​

Question 43

Superconductors: Materials acquire zero __________ to the flow of charge.​

Answer 43

resistance; zero resistance aka infinite conductivity

Question 44

If a charged selenium plate is exposed to a pattern of light, the charge will

Answer 44

leak away only from the areas exposed to light.​

Question 45

Once electric current is established in a superconductor, the electrons flow

Answer 45

indefinitely.​

Question 46

With no electrical resistance, ______ passes through a superconductor without losing energy. ​

Answer 46

current; No heat loss occurs when charges flow.​

Question 47

Resistance of a material to the flow of electric charge through it?

Answer 47

Electrical resistance; measured in ohms.

Question 48

Consider two insulated metal spheres A and B.​ They touch each other, so in effect they form a ​

Answer 48

single uncharged conductor.

Question 49

​When a negatively charged rod is brought near A, electrons in the metal, being free to move,

Answer 49

are repelled as far as possible until their mutual repulsion is big enough to balance the influence of the rod. Thus, the charge is redistributed.

Question 50

​If the two insulated metal spheres A and B are separated while the rod is still present,

Answer 50

each will be equal and oppositely charged.​

Question 51

An electron buzzing around the atomic nucleus produces an

Answer 51

electron cloud.​

Question 52

The unit of measurement for electric potential?

Answer 52

Volt; V = E / q 1 volt = 1 joule / 1 coulomb

Question 53

The energy stored in a capacitor comes from

Answer 53

the work required to charge it. ​

Question 54

Like charges

Answer 54

repel

Question 55

Opposite charges

Answer 55

attract

Question 56

Differences between the charge of an electron versus the charge of a proton:

Answer 56

The charge of an electron is equal in magnitude to the charge of a proton, but opposite in sign.

Question 57

If you scuff electrons onto your feet while walking across a rug, are you negatively or positively charged?

Answer 57

Negatively charged; You have more electrons after you scuff your feet, so you are negatively charged. The rug is positively charged.

Question 58

If a proton at a particular distance from a charged particle is repelled with a given force, by how much will the force decrease when the proton is 3 times farther away from the particle?

Answer 58

It decreases to 1/9 its original value. If the proton is 5 times farther away it will decrease to 1/25 its original value.

Question 59

The negative charge at the bottom of the cloud induces a _______ charge at the surface of the ground below.

Answer 59

positive

Question 60

A charged comb attracts an uncharged piece of paper because the force of attraction for the closer charge is _______ than the force of ________ for the farther charge.

Answer 60

greater; repulsion the force of attraction for the closer charge is greater than the force of repulsion for the farther charge.

Question 61

The negatively charged balloon polarizes atoms in the wooden wall and creates a _______ charged surface, so the balloon sticks to the wall.

Answer 61

positively

Question 62

An H20 molecule is an electric _______.

Answer 62

dipole; meaning the distribution of electric charge is not perfectly even.

Question 63

Electric charge distributes itself on the surface of all conductors in such a way that the electric field inside the conductors is ______.

Answer 63

zero. An electric field inside any conductor is zero--so long as no electric charge is flowing.

Question 64

Increased potential energy or PE is the result of _____ _____.

Answer 64

work input. When the PE of a mass or charged particle (electric potential) is released it becomes kinetic energy or KE. Electric potential and voltage mean the same thing (electrical potential energy per unit charge).