1

Charges placed on a conductor ____________.

Need a Hint?

A) spread out over the surface of the conductor

B) stay where they are placed

C) gather in the center of the conductor

D) vanish after a few moments

2

If the positive charge of an atom's nucleus exactly balances the negative charge of the surrounding electrons, the atom is __________.

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A) neutral

B) static

C) electrified

D) positively-charged

3

Materials that allow charges to move about easily are called __________.

Need a Hint?

A) conductors

B) insulators

C) facilitators

D) plastics

4

If the charge of an atom's nucleus is +2 and the charge of the surrounding electrons is -2, the atom is __________.

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A) electrically neutral

B) unstable

C) negatively-charged

D) positively-charged

5

What are the two kinds of electrical charges?

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A) positive and negative

B) static and dynamic

C) high and low

D) destructive and constructive

6

The best explanation for why the phenomenon in the figure below occurs is ____. (18.0K)

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A) the paper bits are gravitationally attracted to the ruler.

B) the opposite electrical charges on the ruler and paper bits are attracted to each other.

C) the paper bits are magnetically attracted to the ruler.

D) the same electrical charges on the ruler and paper bits are attracted to each other.

7

If a positively-charged glass rod is suspended so that it turns easily, and another positively-charged glass rod is brought close to it, the two rods will __________.

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A) not react

B) fuse

C) repel each other

D) attract each other

8

Materials through which electrical charges will not move easily are called __________.

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A) ions

B) conductors

C) grounders

D) insulators

9

If a charge were added to the figure below between the two charges already there, what direction would the net force on it be? (2.0K)

Need a Hint?

A) To the right if charge is positive, to the left if it's negative.

B) To the right, regardless of its sign

C) To the left if charge is positive, to the right if it's negative.

D) This cannot be determined without knowing more about the location of the charge

10

Two negatively-charged bodies, each charged with -7.4×10-6 C, are 0.20 m from each other. What force acts on each particle and in what direction?

Need a Hint?

A) 1.2×101 N, repulsive

B) 2.5×103 N, attractive

C) 1.2×101 N, attractive

D) 3.0×105 N, repulsive

11

In the figure below, if the charge on the rod were positive, what effect, if any, would this have on the final result? (16.0K)

Need a Hint?

A) The left sphere would still be positive and the right sphere would still be negative, but there would be more total charge on each.

B) It would have no effect.

C) The left sphere would be negatively charged and the right sphere would be positively charged, with the same amount of charge as in the original picture c.

D) The left sphere would still be positive and the right sphere would still be negative, but there would be less total charge on each.

12

A positive and a negative charge, each of magnitude 2.7×10-4 C, are separated by a distance of 10.0 cm. What is the force and direction of the force on each of the particles?

Need a Hint?

A) 6.6×104 N, attractive

B) - 6.6×104 N, attractive

C) 6.6×104 N, repulsive

D) 6.6×102 N, repulsive

13

The SI standard unit of charge is the __________.

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A) ohm

B) coulomb

C) volt

D) joule

14

In the figure below, if q 1 is 2.0 mC, q 2 is 3.0 mC, and the separation between them is 2.5 m, what is the magnitude of the force between them? (2.0K)

Need a Hint?

A) 8600 N

B) 2.4 N

C) 5400 N

D) 220,000 N

15

A force of -8.2×104 N exists between a positive charge of 3.9×10-5 C and a negative charge of -6.7×10-5 C. What distance separates the charges?

Need a Hint?

A) 1.7×10-2 m

B) 1.4×102 m

C) 2.9×10-4 m

D) 1.7×102 m

16

A force of -7.7×103N exists between a positive charge of 5.6×10-4C and a negative charge of -2.1×10-4C. What distance separates the charges?

Need a Hint?

A) 0.14 m

B) 3.7 m

C) 0.37 m

D) 1.4 m

17

Two identical positive charges exert a repulsive force of 5.8 × 10-9 N when separated by a distance of 3.9 × 10-10 m. What is the charge of each?

Need a Hint?

A) -3.1 × 10-19 C

B) 3.1 × 10-19 C

C) 1.0 × 1037 C

D) 4.3 × 1010 C

18

A negative charge of -4.5×10-3 C and a positive charge of 6.5×10-3 C are separated by 0.50 m. What is the magnitude of the force between the two charges?

Need a Hint?

A) 1.1 × 106 N

B) 2.9 × 10-5 N

C) 2.6 × 105 N

D) 2.2 × 106 N

19

In the figure below, if the charge on the rod were decreased, what effect, if any, would this have on the final result? (16.0K)

Need a Hint?

A) The left sphere would still be positive and the right sphere would still be negative, but there would be less total charge on each.

B) The left sphere would still be positive and the right sphere would still be negative, but there would be more total charge on each.

C) It would have no effect.

D) The left sphere would be negatively charged and the right sphere would be positively charged, with the same amount of charge as in the original picture c.

A) the magnitude of the force between two charges is inversely proportional to the magnitude of the charges and proportional to the square of the distance between them

B) the ratio of the potential difference to the current is constant

C) the direction of the magnetic field in a wire is perpendicular to the flow of electric current in the wire

D) the magnitude of the force between two charges is proportional to the magnitude of the charges and inversely proportional to the square of the distance between them

21

An electron's charge is ________ in magnitude and _________ in sign from a proton's charge.

Need a Hint?

A) equal; same

B) unequal; same

C) equal; opposite

D) unequal; opposite

22

In the figure below, if q< 1 is 3.0 mC, q 2 is -7.0 mC, and the separation between them is 3.0 m, what is the magnitude of the force between them? (2.0K)

Need a Hint?

A) 21,000 N

B) 63,000 N

C) 43,000 N

D) 7200 N

23

Charging by induction occurs when __________.

Need a Hint?

A) charge separation is used to charge an object without touching it

B) electric charge causes the leaves of an electroscope to spread apart

C) a neutral body is charged by touching it with a charged body

D) a negatively-charged rod is touched to the knob of an electroscope

24

The magnitude of the charge of an electron is called the __________.

Need a Hint?

A) negative charge

B) secondary charge

C) frequency

D) elementary charge

25

Three particles are placed in a line. The left particle has a charge of -47 mC, the middle, +59 mC, and the right, -91 mC. The middle particle is 55 cm from each of the others. What is the net force on the middle particle?

Need a Hint?

A) 77 N, right

B) 77 N, left

C) 160 N, right

D) 83 N, right

26

A(n) __________ is a device used for detecting electrical charges.

Need a Hint?

A) electroscope

B) conducting sphere

C) oscilloscope

D) cathode-ray tube

27

How far apart are two electrons if they exert a force of repulsion of 2.5 N on each other?

Need a Hint?

A) 9.6 × 1015 m

B) 1.6 × 10-19 m

C) 1.5 × 10-14 m

D) 9.6 × 10-15 m

28

If you increase the distance between two charges, what happens to the force?

Need a Hint?

A) It increases.

B) It decreases.

C) It vanishes.

D) It stays the same.

29

The rule for determining direction of force is __________.

Need a Hint?

A) apply Coulomb's law

B) unlike charges repel, like charges attract

C) direction is determined by magnitude

D) like charges repel, unlike charges attract

30

How far apart are a proton and an electron if they exert a force of attraction of 4.5 N on each other?

Need a Hint?

A) 1.6 × 10-19 m

B) 7.2 × 10-15 m

C) 1.8 × 10-5 m

D) 9.6 × 10-15 m

31

__________ occurs when a neutral body is charged by touching it with a charged body.

Need a Hint?

A) Static discharge

B) Charging by infusion

C) Charging by conduction