Ch 1 Flashcards
What is electrostatics?
The science of static, or stationary, electricity.
How does electrostatics differ from current electricity?
In electrostatics, charges do not flow.
What happens when you run a plastic comb through your hair?
The comb becomes charged and can attract small pieces of paper.
Why does the paper stick to the charged comb?
The charged comb induces an opposite charge in the paper, and opposite charges attract.
What are the two kinds of electric charge?
Negative charge and positive charge.
What charge does a plastic comb have after being rubbed on hair?
Negative charge.
What charge do the pieces of paper have when attracted to a charged comb?
Positive charge.
What occurs when you touch a metal sink or door handle?
You may feel a jolt due to static electricity.
What happens to positive charges when you touch isolated conductors?
Positive charges flow through your body to ground.
Fill in the blank: Electrostatics are usually experienced in electrical _______.
insulators.
What are the three main particles that make up an atom?
Proton, neutron, electron
Protons are positively charged, neutrons are uncharged, and electrons are negatively charged.
What is the nucleus of an atom composed of?
Protons and neutrons
The nucleus is held together by the strong nuclear force.
What force holds electrons in orbit around the nucleus?
Attractive electric forces
Electrons are attracted to the positively charged protons in the nucleus.
What is the approximate distance that electrons extend from the nucleus?
10 m
This distance is on the order of magnitude from the nucleus.
What is the mass of a proton?
1.67262 x 10^-27 kg
The mass of the proton is nearly the same as that of the neutron.
What is the mass of a neutron?
1.675 x 10^-27 kg
The mass of the neutron is almost equal to that of the proton.
What is the mass of an electron?
9.10938356 x 10^-31 kg
The mass of the electron is about 1000 times less than that of protons and neutrons.
True or False: The strong nuclear force has a long range.
False
The strong nuclear force has a short range.
What is the role of quarks in the atomic structure?
They combine to form protons and neutrons
Quarks are the fundamental constituents of protons and neutrons.
Fill in the blank: All materials are composed of _______.
atoms
Atoms are the basic building blocks of ordinary matter.
What determines the charge on an atom?
The total number of subatomic particles that make it up.
What are the charges of the subatomic particles?
- Proton: + charge
- Neutron: no charge (neutral)
- Electron: - charge
Where are protons located in an atom?
In the nucleus.
Where are electrons located in an atom?
Outside of the nucleus in an electron cloud.
What is the charge of a proton in coulombs?
+1.60 x 10^-19 C
What is the charge of an electron in coulombs?
-1.60 x 10^-19 C
Why are atoms electrically neutral?
They have the same number of protons and electrons.
How many protons and electrons does a nitrogen atom have?
7 protons and 7 electrons.
What is the result of the charges of protons and electrons in a nitrogen atom?
Total charge: 7(+e) + 7(-e) = 0.
What force results from the different charges on electrons and protons?
An attractive Coulomb force.
What keeps electrons in their relatively constant orbit around the nucleus?
The balance of attractive forces and centrifugal forces.
What happens to the charge of objects during charging processes?
Charge is transferred from one object to another; it is not created or destroyed.
What is the principle of conservation of charge?
The algebraic sum of all electric charges in any closed system is constant.
What happens to the charge of a comb after it is rubbed on hair?
The comb becomes negatively charged, and the hair becomes positively charged.
True or False: Atoms can easily lose protons.
False.
Fill in the blank: The total electric charge on two objects together does not _______.
change.
What is the fundamental principle regarding electric charges in a closed system?
Charge can be transferred between objects, but charge is neither created nor destroyed
This principle illustrates the conservation of electric charge.
What happens to the charge when two spheres come into contact?
The charge is distributed evenly between both spheres
For example, if one sphere has -8e and the other has 0e, they will each have -4e after contact.
If sphere R has -8e and sphere S has +6e, what is the charge on sphere S after it contacts sphere R?
-4e
The charge is calculated as (0e - 8e)/2 when R and S are in contact.
What is the total charge of the system consisting of spheres R, S, and T after the described procedures?
-2e
The net charge remains constant before and after the charge redistribution.
True or False: Electric charge can be created in a closed system.
False
Charge is conserved; it can only be transferred, not created or destroyed.
Fill in the blank: Charge is a fundamental quantity like _______.
mass
What is the result of sphere S touching sphere T after contacting sphere R?
The charges are redistributed, maintaining the system’s overall charge
The final charge on each sphere after contact will reflect the conservation of charge.
What is the charge on sphere T after it has been in contact with sphere S, assuming S had -4e before the contact?
+6e
This is based on the charge distribution when S and T touch.
What is the initial charge of sphere R in the example?
-8e
What charge does sphere S have before it contacts sphere T?
-4e
