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Physics Chapter 22

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Electrons were removed.

Removing an electron causes the atom to have more protons, which have a positive charge, than electrons, which have a negative charge.
What causes an atom to become positively charged?
Protons were added.
Electrons were removed.
Either protons were added, or electrons were removed.
Electrons were added.
positively charged

Since electrons are negatively charged, removing electrons from at atom causes the atom to become positively charged.
If the atoms of one object (initially neutral) have electrons rubbed off through friction with a second object, the first object becomes ________.
positively charged
negatively charged
neutral in charge
It's impossible to say.
electrons

The outer electrons of atoms of certain materials are very weakly bonded, so they can easily be ripped off and transferred to other materials.
The basic reason why things become electrically charged is that the atoms (or molecules) of some materials hold on to their _______ better than those of other materials.
electrons
protons
neutrons
decreases by a factor of 4

The electric force gets weaker when the distance increases. Review Lesson 1 in the tutorial for additional help

Just like gravity, the electric force is inversely proportional to the square of the distance between the particles.
If the distance between two charged objects is doubled, the resulting electric force on each object __________.
increases by a factor of 2
increases by a factor of 4
decreases by a factor of 2
decreases by a factor of 4
upward

The horizontal components of the electric fields due to each of the two charges exactly cancel out (since the cross is directly above the midpoint), so only the vertical components add up.
In what direction is the electric field at the location depicted by the red cross in the figure?
They would be attracted to each other.

Since one object is attracted to object A and one object is repelled by object A, either object B is positively charged and object C is negatively charged, or visa versa.
Object A is attracted to object B and repelled by object C. All three objects are charged. What would happen if object B and object C were brought together?
They would be attracted to each other.
They would be repelled by each other.
They would be neither repelled nor attracted to each other.
Both objects must be charged, either both negatively or both positively.

Like charges are repelled by each other; it is impossible to determine whether both objects are negatively charged or positively charged based on the information given.
Object A and object B are both hanging by a string, as shown in the figure. Which statement must be true?

Both objects must be positively charged.
Object A and object B must have the same net charge.
Object A and object B must have opposite charges.
Both objects must be charged, either both negatively or both positively.
More than one of the above statements are true.
Some electrons in conductors are weakly attached to the atoms, and all electrons in insulators are strongly attached to the atoms.

A small electric field within the conductor causes the electrons to drift through the material, conducting electricity.

Since conductors have electrons have electrons that are weakly attached it causes more electrons to drift away or to the conductor,
What is the main difference between a conductor, such as copper, and an insulator, such as plastic?
Conductors are charged, and insulators are neutral.
Some electrons in conductors are weakly attached to the atoms, and all electrons in insulators are strongly attached to the atoms.
Conductors have more excess electrons than insulators.
voltage difference between the two ends of a wire
What is the flow of current proportional to?
voltage at one end of the wire
voltages at both ends of the wire
voltage difference between the two ends of a wire
The lamp does not light up because there is no voltage difference applied across it.
What happens to a lamp when you take both ends of the wire connected to it and hold them to the same side of the 12-volt terminal of battery, and why?
The lamp lights up because voltage is applied to it.
The lamp does not light up because there is no voltage difference applied across it.
The lamp does not light up, because there is no voltage applied to it.
The lamp lights up because a voltage difference is applied to it.
The lamp lights up because there is a voltage difference applied to it.
What happens when you have a voltage difference between the two ends of the lamp, and why?
The lamp lights up because voltage is applied to it.
The lamp does not light up, because there is no voltage applied to it.
The lamp lights up because there is a voltage difference applied to it.
volts

joules: is the unit for electric potential energy

coulombs: is the unit for charge

conduction:The process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material.
Electric potential, unlike electric potential energy, is measured in units of _______.
coulombs
volts
conduction
joules
electrical

Atoms bond with each other by reacting to each other's electrons of their outer shells, (outer orbital) .
Which force binds atoms together to form molecules?
centripetal
gravitational
electrical
nuclear
none of these
electrical.

Atoms bond with each other by reacting to each other's electrons of their outer shells, (outer orbital) .
The fundamental force underlying all chemical reactions is
electrical.
centripetal.
nuclear.
gravitational.
None of the above choices are correct.
electrons that surround the nucleus.

neutrons of the nucleus, which have a positive charge, determine the properties of an atom. If electrons, which are negatively charged. are removed or added to that atom it gains a charge making it an ion. If an atom has the same number of electrons as protons then it has a zero net charge.
In an electrically neutral atom the number of protons in the nucleus is equal to the number of
neutrons in the nucleus.
electrons that surround the nucleus.
Choices A and B are both correct.
Choices A and B are both incorrect.
protons than electrons.

protons of the nucleus, which have a positive charge, determine the properties of an atom. If electrons, which are negatively charged. are removed or added to that atom it gains a charge making it an ion. If an atom has the same number of electrons as protons then it has a zero net charge.
A positive ion has more
protons than neutrons.
electrons than neutrons.
protons than electrons.
electrons than protons.
neutrons than protons.
positive ion.

An atom's protons are usually constant, and if are changed for some reason, will in turn change the element of the atom.

So while the nucleus of an atom usually stays constant, the electrons can come and go depending on the outer shell of the location of electrons in it, and can cause the atom to become a negative ion if it gains 1 or more electrons, or a positive ion if it loses one or more electrons.
Strip electrons from an atom and the atom becomes a
negative ion.
different element.
positive ion.
molecule.
can be neither created nor destroyed.

This means when electrons are transferred during a charge, no electrons are created or destroyed.
To say that electric charge is conserved is to say that electric charge
may occur in an infinite variety of quantities.
can be neither created nor destroyed.
is a whole number multiple of the charge of one electron.
will interact with neighboring electric charges.
is sometimes negative.
a specific large number of electrons.

The unit of electric charge, the coulomb, 1C

is the charge associated with 6.25×10⁶ electrons
The unit of electric charge, the coulomb, is the charge on
a specific large number of electrons.
a quark.
a specific number of neutrons.
one electron.
a neutron.
repel or attract.

Gravity only attracts
A main difference between gravitational and electric forces is that electrical forces
attract.
are weaker.
obey the inverse-square law.
repel or attract.
act over shorter distances.
close together.

just like gravity the electric field works works off the inverse square law.

It decreases inversely as the square of the distance between the two charged objects are increased.
The electrical force between charges is strongest when the charges are
close together.
far apart.
The electric force is constant everywhere.
magnitude and separation distance.

According to F=k q1*q2/d2

force is directly proportional to the charged bodies (magnitude) and inversely proportional to the distance between them.
The electrical force between charges depends only on the charges'
separation distance.
magnitude.
magnitude and separation distance.
None of the above choices are correct.
negatively charged.

It becomes negatively charged because the the question say "rub electrons from" meaning when the comb move through your hair, it took electrons from the your hair and transferred them to the comb making the atoms on it more negative.
Rub electrons from your hair with a comb and the comb becomes
positively charged.
discharged.
negatively charged.
attract each other
An electron and a proton
attract each other.
neither attract nor repel each other.
repel each other.
its charges have been rearranged.

an object that is polarized has, does not have any free electron to migrate in or out of it. due to the high conduction of the material. But instead it rearranges the atoms so that it has more positive or negative charges at one part of itself.
To say that an object is electrically polarized is to say
it is electrically charged.
its charges have been rearranged.
it is to some degree magnetic.
it is only partially conducting.
its internal electric field is zero.
either positively or negatively.

This is because the balloon was first charged, and was able to induce an opposite surface charge on the wall.
A balloon will stick to a wooden wall if the balloon is charged
negatively.
positively.
either positively or negatively.
None of the above choices are correct.
charge.

Volts= Joules / Coulombs

or

Force = energy /charge
Electric potential, measured in volts, is the ratio of electric energy to amount of electric
voltage.
current.
charge.
resistance.
None of the above choices are correct.
None of the above choices are correct.
The electric field inside the dome of a Van de Graaff generator
depends on the volume of the dome
depends on the amount of charge the outside of dome.
Choices A and B are both correct.
None of the above choices are correct.
quadruples.


according to
F=k q1*q2/d2

distance is squared
and the closer the charged objects are the higher the electrical force, according the the inverse square rule.
When the distance between two charges is halved, the electrical force between the charges
is reduced by 1/4.
quadruples.
doubles.
halves.
None of the above choices are correct.
the same.

This follows newton's 3d laws with every action there is an equal and opposite reaction.
Particle A has twice the charge of nearby particle B. Compared to the force on Particle A, the force on Particle B is
four times as much.
half as much.
twice as much.
the same.
None of the above choices are correct.
net charge has been created or destroyed.

This means when electrons are transferred during a charge, no electrons are created or destroyed.
To say that electric charge is conserved means that no case has ever been found where the
net amount of negative charges on an object is unbalanced by positive charge on another object.
total amount of charge on an object has increased.
net charge has been created or destroyed.
total charge on an object has changed.
None of the above choices are correct.
none of these

Something is a conductor when it's atoms have loose electrons in in their outer shell

Something is a good insulator when the electrons of their outer shell are tightly bound.
A conductor differs from an insulator in that a conductor
has more energy than an insulator.
has faster moving molecules.
has more protons than electrons.
has more electrons than protons.
none of these
a proton.
The direction of an electric field is the direction of the force that the field would exert on
an electron.
an atom.
a proton.
a molecule.
a neutral test charge.
None of the above choices are correct.

Its 4 times less, due to the inverse square law
The electric field around an isolated electron has a certain strength 1 cm from the electron. The electric field strength 2 cm from the electron is
the same.
four times as much.
half as much.
twice as much.
None of the above choices are correct.
10 J.
Assume that 10 J of work is needed to push a charge, at rest, into an electric field. After the charge is released there, it flies back to its starting position and its kinetic energy there will be
zero.
10 J.
more than 10 J.
5 J.
impossible to predict without additional information.
fall closer together.

The leaves like the rest of the device get the same charge, and cause both leaves to repel each other.
An electroscope is charged positively as shown by foil leaves that stand apart. As a negative charge is brought close to the electroscope, the leaves
spread apart further.
fall closer together.
do not move.
loosely bound.

protons of the nucleus, which have a positive charge, determine the properties of an atom. If electrons, which are negatively charged. are removed or added to that atom it gains a charge making it an ion. If an atom has the same number of electrons as protons then it has a zero net charge.
Charge carriers in a metal are electrons rather than protons because electrons are
negative.
loosely bound.
smaller.
all of these
none of these
wood

Because Iron. aluminum. steel are good conductors and can ground the transfer of electrons to the ground.
In the unlikely case of a lightning strike, it is worse to be inside a building framed with
iron.
aluminum.
steel.
wood.
charge and energy.
Normally a small party balloon charged to several thousand volts will have a relatively small amount of
charge.
charge and energy.
energy.
neither charge nor energy.
energy.
You can touch a 100,000-volt Van de Graaff generator with little harm because although the voltage is high, the relatively small amount of charge means there is a relatively small amount of
conduction.
polarization.
energy.
electric field.
16 N.

4 squared = 16

according to the inverse square law
Two charges separated by one meter exert 1-N forces on each other. If the charges are pushed to 1/4 meter separation, the force on each charge will be
2 N.
8 N.
4 N.
1 N.
16 N.
0.11 N.

according to the inverse square law

1/3 =1/3

1/3 squared= .11
Two charges separated by one meter exert 1-N forces on each other. If the charges are pulled to 3-m separation distance, the force on each charge will be
0 N.
0.11 N.
9 N.
0.33 N.
3 N.
Electricity
General term for electrical phenomena, much like gravity has to do with gravitational phenomena, or sociology with social phenomena.
Electrostatics
The study of electric charge at rest (not in motion, as in electric currents).
Conservation of charge
Electric charge is neither created nor destroyed. The total charge before an interaction equals the total charge after.
Coulomb's law
The relationship between electrical force, charge, and distance: F = k · q₁q₂/d²
If the charges are alike in sign, the force is repulsive; if the charges are unlike, the force is attractive.
Coulomb
The SI unit of electrical charge. One coulomb (symbol C) is equal to the total charge of 6.25 × 10¹⁸ electrons.
Conductor
Any material having free charged particles that easily flow through it when an electric force acts on them.
Insulator
A material without free charged particles and through which charge does not easily flow.
Semiconductor
A device composed of material not only with properties that fall between a conductor and an insulator but with resistance that changes abruptly when other conditions change, such as temperature, voltage, and electric or magnetic fields.
Superconductor
A material that is a perfect conductor with zero resistance to the flow of electric charge.
Charging by contact
Transfer of electric charge between objects by rubbing or simple touching.
Charging by induction
Redistribution of electric charges in and on objects caused by the electrical influence of a charged object close by but not in contact.
Electrically polarized
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.
Electric field
Defined as force per unit charge, it can be considered to be an "aura" surrounding charged objects and is a storehouse of electric energy. 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.
Electric potential energy
The energy a charged object possesses by virtue of its location in an electric field.
Electric potential
The electric potential energy per unit of charge, measured in volts, and often called *voltage:
Voltage = electric potential energy/amount of charge*
Capacitor
An electrical device--in its simplest form, a pair of parallel conducting plates separated by a small distance--that stores electric charge and energy.
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