Electrostatics
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
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1. The charge of an electron is
a. positive.
b. negative.
c. Electrons have no charge.
2. Atomic nuclei of almost all elements consist of
a. only neutrons.
b. protons and electrons.
c. neutrons and electrons.
d. only protons.
e. protons and neutrons.
3. Two like charges
a. neutralize each other.
b. repel each other.
c. must be neutrons.
d. attract each other.
e. have no effect on each other.
4. Protons and electrons
a. attract each other.
b. repel each other.
c. do not interact.
5. The fundamental force underlying all chemical reactions is
a. electrical.
b. gravitational.
c. centripetal.
d. nuclear.
e. none of the above
6. Electrical forces between charges are strongest when the charges are
a. far apart.
b. close together.
c. The electrical force is constant everywhere.
7. Coulomb's law says that the force between any two charges depends
a. directly on the size of the charges.
b. inversely on the square of the distance between the charges.
c. both A and B
d. none of the above
8. Two charges are separated by a certain distance. If the magnitude of each charge is doubled, the force on each
charge is
a. halved.
b. doubled.
c. tripled.
d. quadrupled.
9. When the distance between two charges is halved, the electrical force between the charges
a. doubles.
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b. reduces to one fourth.
c. halves.
d. quadruples.
e. none of the above
The net charge of a nonionized atom
a. depends only on the number of electrons it has.
b. is zero.
c. usually cannot be determined.
d. depends only on the number of protons it has.
A positive ion has
a. more electrons than protons.
b. more protons than electrons.
c. a +1 charge always.
d. one proton.
Conservation of charge means that
a. the total amount of charge in the universe is constant.
b. no experimenter has ever seen a single charge destroyed by itself.
c. electrons by themselves can be neither created nor destroyed.
d. charge can be neither created nor destroyed.
e. all of the above
If you comb your hair and the comb becomes positively charged, your hair becomes
a. uncharged.
b. positively charged.
c. negatively charged.
To say that electric charge is conserved means that no case has ever been found where
a. the total amount of charge on an object has increased.
b. one object has more charge than another object.
c. the total charge on an object has changed.
d. net charge has been created or destroyed.
e. none of the above
A difference between electrical forces and gravitational forces is that electrical forces include
a. infinite range.
b. repulsive interactions.
c. the inverse square law.
d. separation distance.
e. none of the above
The common hydrogen atom consists of
a. one electron.
b. one proton and one electron.
c. one proton.
d. two protons, one neutron, and two electrons.
e. one neutron and one electron.
In a good insulator, electrons are usually
a. not moving at all.
b. free to move around after an impurity has been added.
c. free to move around.
d. tightly bound in place.
e. semi-free to move around.
Objects can be charged by
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a. induction.
b. friction.
c. touching.
d. all of the above
e. none of the above
Charge carriers in a metal are electrons rather than protons, because electrons are
a. relatively far from a nucleus.
b. loosely bound.
c. lighter.
d. all of the above
e. none of the above
To be safe in the unlikely case of a lightning strike, it is best to be inside a building framed with
a. steel.
b. wood.
c. either A or B.
A conductor differs from an insulator in that a conductor has
a. more protons than electrons.
b. faster-moving molecules.
c. more electrons than protons.
d. more electrons than an insulator.
e. none of the above
Much electronic equipment contains transistors and diodes that are made from semiconductors.
Semiconductors
a. can be very good insulators.
b. can conduct electricity.
c. contain helpful impurities.
d. all of the above
e. none of the above
A negatively charged rod is brought near a metal can that rests on a wood table. You touch the opposite side
of the can momentarily with your finger. The can is then
a. positively charged.
b. negatively charged.
c. charged the same as it was.
d. uncharged.
An electroscope is charged positively, as shown by foil leaves that stand apart. As a negatively charged rod
is brought close to the electroscope, the leaves
a. spread farther apart.
b. do not move.
c. move closer together.
Lightning bolts occur between
a. clouds and the ground.
b. clouds.
c. both A and B.
To charge an object by induction, the process of grounding
a. may or may not occur.
b. always occurs.
When a charged cloud passes overhead, the ground below is charged by
a. induction.
b. polarization.
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c. deduction.
d. electrification.
Bring a charged object near a conductor and then momentarily touch the conductor. This demonstrates charge
by
a. deduction.
b. polarization.
c. induction.
d. electrification.
A rubbed balloon will stick to a wooden wall, which demonstrates charge
a. transfer.
b. potential.
c. conservation.
d. polarization.
Electrical polarization occurs when
a. an electron is at a different location than a proton.
b. charge distribution in a neutral molecule separates.
c. the electron and the proton are on different sides of an atom.
d. an atom vibrates in a single direction.
e. none of the above
The reason a charged balloon will stick to a wall is that
a. induced opposite charges in the wall are closer than other wall charges.
b. the rubber of the balloon simply sticks to walls.
c. electrons transfer back and forth between the wall and the balloon.
d. the charge is slightly sticky and acts like glue.
e. none of the above
The charge distribution in some molecules is permanently separated into positive and negative regions. Such
molecules are called
a. ionized molecules.
b. electric dipoles.
c. coulomb molecules.
d. induced molecules.
e. insulators.
Two charged particles held close to each other are released. As they move, the force on each particle
increases. Therefore, the particles have
a. opposite signs.
b. the same sign.
c. charges that cannot be determined
Two charged particles held close to each other are released. As the particles move, the velocity of each
increases. Therefore, the particles have
a. the same sign.
b. opposite signs.
c. charges that cannot be determined.
A positive charge and a negative charge held near each other are released. As they move, the force on each
particle
a. increases.
b. stays the same.
c. decreases.
Two charged particles held near each other are released. As they move, the acceleration of each decreases.
Therefore, the particles have
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a. opposite signs.
b. the same sign.
c. charges that can not be determined.
How many different kinds of force would act on a proton placed in both an electric field and a gravitational
field?
a. one.
b. none.
c. two.
The SI unit of charge is the
a. ohm.
b. joule.
c. coulomb.
d. ampere.
e. newton.
Particle A has twice as much charge as particle B. Compared to the force on particle A, the force on particle B
is
a. half as much.
b. two times as much.
c. four times as much.
d. the same.
e. none of the above
The electrostatic force between two charges located 8 meters apart is 0.10 N. What will the force be between
these charges when they are located 2 meters apart?
a. 0.01 N
b. 0.03 N
c. 0.1 N
d. 0.8 N
e. 1.6 N
A 2-C charge and a 4-C charge attract each other with 10 N of force. How much will a 2-C charge and a 12-C
charge attract each other when placed the same distance apart?
a. 5 N
b. 12 N
c. 10 N
d. 30 N
e. 60 N
Two charges separated a distance of 1.0 meter exert a 2.0-N force on each other. If the charges are pushed to a
separation of
meter, the force on each charge will be
a. 2.0 N.
b. 1.5 N.
c. 3.0 N.
d. 6.0 N.
e. 18.0 N.
____ 43. Two charges separated by a distance of 1 meter exert a 20-N force on each other. If the charges are pulled to a
2 meter separation distance, the force on each charge will be
a. 0 N.
b. 5 N.
c. 10 N.
d. 40 N.
e. 80 N.
____ 44. Two charges separated by a distance of 1 meter exert a 2-N force on each other. If the magnitude of each
charge is doubled, the force on each charge is
a. 2 N.
b. 4 N.
c. 8 N.
d. 16 N.
e. none of the above