Ch 1

Question 1

What is electrostatics?

Answer 1

The science of static, or stationary, electricity.

Question 2

How does electrostatics differ from current electricity?

Answer 2

In electrostatics, charges do not flow.

Question 3

What happens when you run a plastic comb through your hair?

Answer 3

The comb becomes charged and can attract small pieces of paper.

Question 4

Why does the paper stick to the charged comb?

Answer 4

The charged comb induces an opposite charge in the paper, and opposite charges attract.

Question 5

What are the two kinds of electric charge?

Answer 5

Negative charge and positive charge.

Question 6

What charge does a plastic comb have after being rubbed on hair?

Answer 6

Negative charge.

Question 7

What charge do the pieces of paper have when attracted to a charged comb?

Answer 7

Positive charge.

Question 8

What occurs when you touch a metal sink or door handle?

Answer 8

You may feel a jolt due to static electricity.

Question 9

What happens to positive charges when you touch isolated conductors?

Answer 9

Positive charges flow through your body to ground.

Question 10

Fill in the blank: Electrostatics are usually experienced in electrical _______.

Answer 10

insulators.

Question 11

What are the three main particles that make up an atom?

Answer 11

Proton, neutron, electron

Protons are positively charged, neutrons are uncharged, and electrons are negatively charged.

Question 12

What is the nucleus of an atom composed of?

Answer 12

Protons and neutrons

The nucleus is held together by the strong nuclear force.

Question 13

What force holds electrons in orbit around the nucleus?

Answer 13

Attractive electric forces

Electrons are attracted to the positively charged protons in the nucleus.

Question 14

What is the approximate distance that electrons extend from the nucleus?

Answer 14

10 m

This distance is on the order of magnitude from the nucleus.

Question 15

What is the mass of a proton?

Answer 15

1.67262 x 10^-27 kg

The mass of the proton is nearly the same as that of the neutron.

Question 16

What is the mass of a neutron?

Answer 16

1.675 x 10^-27 kg

The mass of the neutron is almost equal to that of the proton.

Question 17

What is the mass of an electron?

Answer 17

9.10938356 x 10^-31 kg

The mass of the electron is about 1000 times less than that of protons and neutrons.

Question 18

True or False: The strong nuclear force has a long range.

Answer 18

False

The strong nuclear force has a short range.

Question 19

What is the role of quarks in the atomic structure?

Answer 19

They combine to form protons and neutrons

Quarks are the fundamental constituents of protons and neutrons.

Question 20

Fill in the blank: All materials are composed of _______.

Answer 20

atoms

Atoms are the basic building blocks of ordinary matter.

Question 21

What determines the charge on an atom?

Answer 21

The total number of subatomic particles that make it up.

Question 22

What are the charges of the subatomic particles?

Answer 22

• Proton: + charge
• Neutron: no charge (neutral)
• Electron: - charge

Question 23

Where are protons located in an atom?

Answer 23

In the nucleus.

Question 24

Where are electrons located in an atom?

Answer 24

Outside of the nucleus in an electron cloud.

Question 25

What is the charge of a proton in coulombs?

Answer 25

+1.60 x 10^-19 C

Question 26

What is the charge of an electron in coulombs?

Answer 26

-1.60 x 10^-19 C

Question 27

Why are atoms electrically neutral?

Answer 27

They have the same number of protons and electrons.

Question 28

How many protons and electrons does a nitrogen atom have?

Answer 28

7 protons and 7 electrons.

Question 29

What is the result of the charges of protons and electrons in a nitrogen atom?

Answer 29

Total charge: 7(+e) + 7(-e) = 0.

Question 30

What force results from the different charges on electrons and protons?

Answer 30

An attractive Coulomb force.

Question 31

What keeps electrons in their relatively constant orbit around the nucleus?

Answer 31

The balance of attractive forces and centrifugal forces.

Question 32

What happens to the charge of objects during charging processes?

Answer 32

Charge is transferred from one object to another; it is not created or destroyed.

Question 33

What is the principle of conservation of charge?

Answer 33

The algebraic sum of all electric charges in any closed system is constant.

Question 34

What happens to the charge of a comb after it is rubbed on hair?

Answer 34

The comb becomes negatively charged, and the hair becomes positively charged.

Question 35

True or False: Atoms can easily lose protons.

Answer 35

False.

Question 36

Fill in the blank: The total electric charge on two objects together does not _______.

Answer 36

change.

Question 37

What is the fundamental principle regarding electric charges in a closed system?

Answer 37

Charge can be transferred between objects, but charge is neither created nor destroyed ## Footnote This principle illustrates the conservation of electric charge.

Question 38

What happens to the charge when two spheres come into contact?

Answer 38

The charge is distributed evenly between both spheres ## Footnote For example, if one sphere has -8e and the other has 0e, they will each have -4e after contact.

Question 39

If sphere R has -8e and sphere S has +6e, what is the charge on sphere S after it contacts sphere R?

Answer 39

-4e ## Footnote The charge is calculated as (0e - 8e)/2 when R and S are in contact.

Question 40

What is the total charge of the system consisting of spheres R, S, and T after the described procedures?

Answer 40

-2e ## Footnote The net charge remains constant before and after the charge redistribution.

Question 41

True or False: Electric charge can be created in a closed system.

Answer 41

False ## Footnote Charge is conserved; it can only be transferred, not created or destroyed.

Question 42

Fill in the blank: Charge is a fundamental quantity like _______.

Answer 42

mass

Question 43

What is the result of sphere S touching sphere T after contacting sphere R?

Answer 43

The charges are redistributed, maintaining the system's overall charge ## Footnote The final charge on each sphere after contact will reflect the conservation of charge.

Question 44

What is the charge on sphere T after it has been in contact with sphere S, assuming S had -4e before the contact?

Answer 44

+6e ## Footnote This is based on the charge distribution when S and T touch.

Question 45

What is the initial charge of sphere R in the example?

Answer 45

-8e

Question 46

What charge does sphere S have before it contacts sphere T?

Answer 46

-4e