# Quiz 22: Current and Resistance

Physics & Astronomy

Q 1Q 1

If a quantity you calculated has units of A ∙ s, what is that quantity?
A)potential
B)resistivity
C)resistance
D)capacitance
E)charge

Free

Multiple Choice

E

Q 2Q 2

When current is flowing in an ordinary metal wire, the magnitude of the average velocity of the electrons is closest to
A)10 m/s.
B)the speed of light.
C)1 mm/s.
D)1 km/s.
E)1 m/s.

Free

Multiple Choice

C

Q 3Q 3

When a current flows through a metal wire, the moving charges are
A)only protons.
B)only electrons.
C)both protons and electrons.
D)positive metal ions.
E)negative metal ions.

Free

Multiple Choice

B

Q 4Q 4

When a current flows through an ionic liquid such as salty water, the moving charges are
A)only protons.
B)only electrons.
C)only negative ions.
D)only positive ions.
E)both positive and negative ions.

Free

Multiple Choice

Q 5Q 5

If a quantity you calculated has units of Ω ∙ m what is that quantity?
A)potential
B)resistivity
C)resistance
D)capacitance
E)charge

Free

Multiple Choice

Q 6Q 6

If a quantity you calculated has units of , what is that quantity?
A)potential
B)resistivity
C)resistance
D)capacitance
E)charge

Free

Multiple Choice

Q 7Q 7

The figure shows electrons passing through a resistor. The arrow shows the direction in which the electrons are moving. Which of the following statements are correct? (There could be more than one correct choice.)
A)The electrons are moving slower at point b than at point a.
B)The electric potential is higher at point b than at point a.
C)The electric potential is lower at point b than at point a.
D)The electrons are losing electric potential energy as they move through the resistor from a to b.
E)The speed of the electrons at point b is the same as it is at point a.

Free

Multiple Choice

Q 8Q 8

The figure shows conventional current passing through a resistor. The arrow shows the direction in which this conventional current is flowing. Which of the following statements are correct? (There could be more than one correct choice.)
A)The charges are moving slower at point b than at point a.
B)The electric potential is lower at point b than at point a.
C)The electric potential is higher at point b than at point a.
D)The current at point b is the same as the current at point a.
E)The electric potential at point b is the same as it is at point a.

Free

Multiple Choice

Q 9Q 9

For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?
A)power
B)resistivity
C)1/(resistivity)
D)resistance
E)1/(resistance)

Free

Multiple Choice

Q 10Q 10

For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?
A)power
B)resistivity
C)1/(resistivity)
D)resistance
E)1/(resistance)

Free

Multiple Choice

Q 11Q 11

For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?
A)current
B)resistivity
C)1/(current)
D)power
E)1/(resistivity)

Free

Multiple Choice

Q 12Q 12

For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?
A)current
B)resistivity
C)1/(current)
D)power
E)1/(resistivity)

Free

Multiple Choice

Q 13Q 13

You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the smallest possible resistance, you should attach the leads to the opposite faces that measure
A)3 cm × 5 cm.
B)3 cm × 8 cm.
C)5 cm × 8 cm.
D)Any pair of faces produces the same resistance.

Free

Multiple Choice

Q 14Q 14

You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the largest possible resistance, you should attach the leads to the opposite faces that measure
A)3 cm × 5 cm.
B)3 cm × 8 cm.
C)5 cm × 8 cm.
D)Any pair of faces produces the same resistance.

Free

Multiple Choice

Q 15Q 15

Copper wire #1 has a length L and a radius b. Copper wire #2 has a length 2L and a radius 2b. Which statement about the resistance across the ends of the wires is true?
A)The resistance of wire #1 is twice as high as that of wire #2.
B)The resistance of wire #1 is equal to that of wire #2.
C)The resistance of wire #1 is half that of wire #2.
D)The resistance of wire #1 is four times higher than that of wire #2.

Free

Multiple Choice

Q 16Q 16

The figure shows a graph of the resistance of a wire as a function of its length. What physical quantities does the slope of this graph represent?
A)the cross-sectional area of the wire
B)the resistivity of the material of which the wire is made
C)the product of the resistivity and the cross-sectional area of the wire
D)the resistivity of the material divided by the cross-sectional area of the wire
E)the reciprocal of the resistivity of the material

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Multiple Choice

Q 17Q 17

A wire of resistivity ρ must be replaced in a circuit by a wire of the same material but four times as long. If, however, the total resistance is to remain as before, the diameter of the new wire must
A)be the same as the original diameter.
B)be one-half the original diameter.
C)be one-fourth the original diameter.
D)be two times the original diameter.
E)be four times the original diameter.

Free

Multiple Choice

Q 18Q 18

The length of a certain wire is kept same while its radius is doubled. What is the new resistance of this wire?
A)It is increased by a factor of 2.
B)It is increased by a factor of 4.
C)It is reduced by a factor of 2.
D)It is reduced by a factor of 4.
E)It is reduced by a factor of 8.

Free

Multiple Choice

Q 19Q 19

The length of a certain wire is kept same while its radius is doubled. What is the new resistivity of this wire?
A)It is increased by a factor of 2.
B)It is increased by a factor of 4.
C)It is reduced by a factor of 2.
D)It is reduced by a factor of 4.
E)It does not change.

Free

Multiple Choice

Q 20Q 20

The length of a certain wire is doubled while its radius is kept constant. What is the new resistance of this wire?
A)It stays the same.
B)It is 2 times as large.
C)It is 3 times as large.
D)It is 4 times as large.
E)It is 1/2 as large.

Free

Multiple Choice

Q 21Q 21

The length of a certain wire is doubled and at the same time its radius is also doubled. What is the new resistance of this wire?
A)It stays the same.
B)It is 2 times as large.
C)It is 4 times as large.
D)It is 1/2 as large.
E)It is 1/4 as large.

Free

Multiple Choice

Q 22Q 22

The length of a certain wire is doubled and at the same time its radius is reduced by a factor of 2. What is the new resistance of this wire?
A)It is 2 times as large.
B)It is 4 times as large.
C)It is 6 times as large.
D)It it 8 times as large.
E)It is 1/2 as large.

Free

Multiple Choice

Q 23Q 23

If a quantity you calculated has units of what is that quantity?
A)potential
B)resistivity
C)resistance
D)capacitance
E)current

Free

Multiple Choice

Q 24Q 24

If a quantity you calculated has units of what is that quantity?
A)potential
B)resistivity
C)resistance
D)capacitance
E)current

Free

Multiple Choice

Q 25Q 25

Which one of the following quantities is equivalent to 1 Ω?
A)1 J/s
B)1 W/A
C)1 V ∙ A
D)1 V/A
E)1 A ∙ s

Free

Multiple Choice

Q 26Q 26

If the length and diameter of a wire of circular cross section are both tripled, the resistance will be
A)unchanged.
B)tripled.
C)increased by a factor of 9.
D)1/3 of what it originally was.
E)1/9 of what it originally was.

Free

Multiple Choice

Q 27Q 27

Consider two copper wires of equal cross-sectional area. One wire has 3 times the length of the other. How do the resistivities of these two wires compare?
A)Both wires have the same resistivity.
B)The longer wire has 3 times the resistivity of the shorter wire.
C)The longer wire has 9 times times the resistivity of the shorter wire.
D)The longer wire has 27 times times the resistivity of the shorter wire.

Free

Multiple Choice

Q 28Q 28

Consider two copper wires of equal cross-sectional area. One wire has 3 times the length of the other. How do the resistances of these two wires compare?
A)Both wires have the same resistance.
B)The longer wire has 1/3 the resistance of the shorter wire.
C)The longer wire has 3 times the resistance of the shorter wire.
D)The longer wire has 9 times times the resistance of the shorter wire.
E)The longer wire has 27 times times the resistance of the shorter wire.

Free

Multiple Choice

Q 29Q 29

Consider two copper wires of equal length. One wire has twice the cross-sectional area of the other. How do the resistances of these two wires compare?
A)The thicker wire has twice the resistance of the thinner wire.
B)The thicker wire has eight times the resistance of the thinner wire.
C)The thicker wire has one-half the resistance of the thinner wire.
D)The thicker wire has four times the resistance of the thinner wire.
E)The thicker wire has one-fourth the resistance of the thinner wire.

Free

Multiple Choice

Q 30Q 30

Consider two copper wires with circular cross-sections and equal lengths. One wire has 3 times the diameter of the other. How do the resistances of these two wires compare?
A)The thicker wire has 1/3 the resistance of the thinner wire.
B)The thicker wire has 1/9 the resistance of the thinner wire.
C)The thicker wire has 3 times the resistance of the thinner wire.
D)The thicker wire has 9 times the resistance of the thinner wire.
E)The thicker wire has times the resistance of the thinner wire.

Free

Multiple Choice

Q 31Q 31

When the current through a resistor is increased by a factor of 4, the power dissipated by the resistor
A)decreases by a factor of 4.
B)decreases by a factor of 16.
C)increases by a factor of 16.
D)increases by a factor of 4.
E)increases by a factor of 2.

Free

Multiple Choice

Q 32Q 32

Which one of the following quantities is equivalent to 1 W?
A)1 V/A
B)1 Ω ∙ m
C)1 V ∙ A
D)1 V/Ω
E)1 A ∙ s

Free

Multiple Choice

Q 33Q 33

A kilowatt-hour is equivalent to
A)1000 W.
B)3600 J.
C)3,600,000 J/s.
D)3,600,000 J.
E)3600 J/s

Free

Multiple Choice

Q 34Q 34

If the resistance in a constant voltage circuit is doubled, the power dissipated by that circuit will
A)increase by a factor of two.
B)increase by a factor of four.
C)decrease to one-half its original value.
D)decrease to one-fourth its original value.

Free

Multiple Choice

Q 35Q 35

If the voltage across a circuit of constant resistance is doubled, the power dissipated by that circuit will
A)be four times as large.
B)be two times as large.
C)decrease to one-half the original power.
D)decrease to one-fourth the original power.

Free

Multiple Choice

Q 36Q 36

If we double the resistance in a circuit but keep the current in it constant, the power dissipated by that circuit will
A)be four times as great.
B)be two times as great.
C)be one-half as great.
D)be one-fourth as great.

Free

Multiple Choice

Q 37Q 37

If the current flowing through a circuit of constant resistance is doubled, the power dissipated by that circuit will
A)quadruple in magnitude.
B)double in magnitude.
C)decrease to one-half of what it was.
D)decrease to one-fourth of what it was.

Free

Multiple Choice

Q 38Q 38

During a period of high power demand, the voltage output of the power company is reduced by 5.0%. By what percentage is the power in a resistor decreased?
A)2.5%
B)5.0%
C)10%
D)15%
E)90%

Free

Multiple Choice

Q 39Q 39

The figure shows a graph of the power dissipated in a resistor as a function of the resistance. What quantity does the slope of this graph represent?
A)the current in the resistor
B)the potential difference across the resistor
C)the reciprocal of the current in the resistor
D)the square of the current in the resistor
E)the resistivity of the resistor

Free

Multiple Choice

Q 40Q 40

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?
A)resistivity
B)resistance
C)energy
D)current
E)capacitance

Free

Multiple Choice

Q 41Q 41

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?
A)1/(current)
B)resistance
C)1/(resistance)
D)current
E)resistivity

Free

Multiple Choice

Q 42Q 42

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?
A)1/(resistance)
B)resistance
C)potential
D)(potential)

^{2}E)1/(potential)Free

Multiple Choice

Q 43Q 43

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?
A)1/(resistance)
B)resistance
C)potential
D)(potential)

^{2}E)1/(potential)Free

Multiple Choice

Q 44Q 44

A 10-A current flows through a wire for 2.0 min. (e = 1.60 × 10

^{-19 }C) (a)How much charge has passed through this wire? (b)How many electrons have passed any point in the wire?Free

Essay

Q 45Q 45

If a charge of 11.4 C passes through a computer in 1.75 min, what is the average current through the computer?

Free

Essay

Q 46Q 46

A current of 5.0 A flows through an electrical device for 10 seconds. How many electrons flow through this device during this time? (e = 1.60 × 10

^{-19 }C) A)0.20 B)20 C)2.0 D)3.1 x E)31 xFree

Multiple Choice

Q 47Q 47

What current is flowing in a wire if 0.67 C of charge pass a point in the wire in 0.30 s?
A)2.2 A
B)0.67 A
C)0.30 A
D)0.20 A

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Multiple Choice

Q 48Q 48

A charge of 12 C passes through an electroplating apparatus in 2.0 min. What is the average current in the apparatus?
A)0.10 A
B)0.60 A
C)1.0 A
D)6.0 A

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Multiple Choice

Q 49Q 49

How much charge must pass by a point in a wire in 10 s for the current inb the wire to be 0.50 A?
A)20 C
B)2.0 C
C)5.0 C
D)0.050 C

Free

Multiple Choice

Q 50Q 50

A total of 2.0 × 10

^{13}electrons pass a given point in a wire in 15 s. What is the current in the wire? (e = 1.60 × 10^{-19 }C) A)1.3 mA B)1.3 A C)0.21 μA D)3.2 μAFree

Multiple Choice

Q 51Q 51

What current is flowing in a resistor if 4.0 × 10

^{16}electrons pass a point in the resistor in 0.50 s? (e = 1.60 × 10^{-19 }C) A)0.013 A B)0.31 A C)6.3 A D)78 AFree

Multiple Choice

Q 52Q 52

If 3.0 × 10

^{15}electrons flow through a section of a wire of diameter 2.0 mm in 4.0 s, what is the current in the wire? (e = 1.60 × 10^{-19 }C) A)0.12 mA B)0.24 mA C)7.5 × 10^{7}A D)7.5 × 10^{14}AFree

Multiple Choice

Q 53Q 53

A electric heater that draws 13.5 A of dc current has been left on for 10 min. How many electrons that have passed through the heater during that time? (e = 1.60 × 10

^{-19 }C) A)1.5 × 10^{22}B)5.1 × 10^{22}C)1.8 × 10^{3}D)8.1 × 10^{3}E)1.0 × 10^{23}Free

Multiple Choice

Q 54Q 54

In an electroplating process, it is desired to deposit 40 mg of silver on a metal part by using a current of 2.0 A. How long must the current be allowed to run to deposit this much silver? The silver ions are singly charged, and the atomic mass of silver is 108 g/mol. (e = 1.60 × 10

^{-19}C, N_{A}= 6.02 × 10^{23}atoms/mol) A)16 s B)18 s C)20 s D)22 sFree

Multiple Choice

Q 55Q 55

A jeweler needs to electroplate gold, having an atomic mass of 196.97 g/mol, onto a bracelet. He knows that the charge carriers in the ionic solution are singly-ionized gold ions, Au

^{+}, and has calculated that he must deposit of gold to reach the necessary thickness. How much current does he need to plate the bracelet in 3.0 hours? (e = 1.60 × 10^{-19}C, N_{A}= 6.02 × 10^{23}atoms/mol) A)9.1 mA B)540 mA C)33 A D)1800 mAFree

Multiple Choice

Q 56Q 56

What potential difference is required across an 8.0-Ω resistor to cause 2.0 A to flow through it?

Free

Essay

Q 57Q 57

The current through a piece of lab equipment must be limited to 2.75 A when it is run by a 120-V dc power supply. What must be the resistance of this equipment?

Free

Essay

Q 58Q 58

What potential difference is required to cause 4.00 A to flow through a resistance of 330 Ω?
A)12.1 V
B)82.5 V
C)334 V
D)1320 V

Free

Multiple Choice

Q 59Q 59

What is the voltage drop across a 5.0-Ω resistor if the current through it is 5.0 A?
A)100 V
B)25 V
C)4.0 V
D)1.0 V

Free

Multiple Choice

Q 60Q 60

A 4000-Ω resistor is connected across a 220-V power source. What current will flow through the resistor?
A)0.055 A
B)1.8 A
C)5.5 A
D)18 A

Free

Multiple Choice

Q 61Q 61

A light bulb operating at 110 V draws 1.40 A of current. What is its resistance?
A)12.7 Ω
B)78.6 Ω
C)109 Ω
D)154 Ω

Free

Multiple Choice

Q 62Q 62

A 12-V battery is connected across a 100-Ω resistor. How many electrons flow through the wire in 1.0 min? (e = 1.60 × 10

^{-}^{19}A)1.5 × 10^{19}B)2.5 × 10^{19}C) C)3.5 × 10^{19}D)4.5 × 10^{19}Free

Multiple Choice

Q 63Q 63

The graph shown in the figure shows the results of measurements of the dc current through a circuit device for various potential differences across it. Assume that all the numbers shown are accurate to two significant figures. What is the resistance of this device?

Free

Essay

Q 64Q 64

The graph shown in the figure shows the results of measurements of the dc current through a circuit device for various potential differences across it. Assume that all the numbers shown are accurate to two significant figures. What is the resistance of this device?

Free

Essay

Q 65Q 65

When a thin copper wire that is 178 m long is connected between a 1.2-V potential difference, a current of 2.0 amps flows through the wire. What is the diameter of this wire? The resistivity of copper is 1.72 × 10

^{-8 }Ω ∙ m.Free

Essay

Q 66Q 66

A 25-m wire of diameter 0.30 mm draws 0.499 A when connected across a 3.0-V potential difference.
(a)What is the resistance of the wire?
(b)What is the resistivity of the material from which the wire is made?

Free

Essay

Q 67Q 67

A certain metal wire has a cross-sectional area of 1.0 cm

^{2}and a resistivity of 1.7 × 10^{-8}Ω ∙ m. How long would it have to be to have a resistance of 1.0 Ω? A)5.9 × 10^{6}m B)5.9 m C)5.9 × 10^{4}m D)590 m E)5.9 kmFree

Multiple Choice

Q 68Q 68

What is the resistance of 1.0 m of a solid cylindrical metal cable having a diameter of 0.40 inches and a resistivity of 1.68 × 10

^{-8}Ω ∙ m? A)0.00012 Ω B)0.00021 Ω C)0.0012 Ω D)0.0021 ΩFree

Multiple Choice

Q 69Q 69

What is the resistance of a cylindrical metal rod 1.0 cm in diameter and 45 m long, if the resistivity of the metal is 1.4 × 10

^{-8}Ω ∙ m? A)0.0063 Ω B)0.0080 Ω C)0.80 Ω D)6.3 ΩFree

Multiple Choice

Q 70Q 70

A certain metal has a resistivity of 1.68 × 10

^{-8}Ω ∙ m. You have a long spool of wire made from this metal. If this wire has a diameter of 0.15 mm, how long should you cut a segment so its resistance will be 15 Ω? A)16 mm B)16 cm C)1.6 m D)16 mFree

Multiple Choice

Q 71Q 71

A 120-m long metal wire having a resistivity of 1.68 × 10

^{-8}Ω ∙ m has a resistance of 6.0 Ω. What is the diameter of the wire? A)0.065 mm B)0.65 mm C)0.65 cm D)0.65 mFree

Multiple Choice

Q 72Q 72

A rod is 4.0 m long and has a square cross-section that is 1.5 cm on each side. An ohmmeter measures 0.040 Ω across its ends. What is the resistivity of the material from which this rod is made?
A)0.023 Ω ∙ m
B)0.015 Ω ∙ m
C)1.5 × 10

^{-4}Ω ∙ m D)2.3 × 10^{-6}Ω ∙ mFree

Multiple Choice

Q 73Q 73

Calculate the current through a 10.0-m long 22-gauge nichrome wire with a radius of 0.321 mm if it is connected across a 12.0-V battery. The resistivity of the nichrome is 1.00 × 10

^{-6}Ω ∙ m. A)30.9 A B)61.8 A C)0.388 A D)0.776 AFree

Multiple Choice

Q 74Q 74

A metal bar is 20 cm long and has a rectangular cross-section measuring 1.0 cm × 2.0 cm. What is the voltage drop along its length when it carries a 4000-A current? The resistivity of the metal is 1.68 × 10

^{-8}Ω ∙ m. A)0.67 V B)0.34 V C)0.067 V D)0.034 VFree

Multiple Choice

Q 75Q 75

A 1.0-m length of nichrome wire has a radius of 0.50 mm and a resistivity of 1.0 × 10

^{-6}Ω ∙ m. When this wire carries a current of 0.50 A, what is the voltage across its ends? A)0.0030 V B)0.32 V C)0.64 V D)1.6 VFree

Multiple Choice

Q 76Q 76

A 1.0-mm diameter extension cord is made of metal having a resistivity of 1.68 × 10

^{-8}Ω ∙ m. When it carries a current of 15 A, what is the potential difference between two points in the cord that are 100 m apart? A)12 V B)23 V C)32 V D)41 VFree

Multiple Choice

Q 77Q 77

How much current will be flowing through a length of copper wire with radius if it is connected to a source supplying The resistivity of the metal is 1.68 × 10

^{-8}Ω ∙ m. A)0 A B)0 × 10^{8}A C)0 nA D)0 AFree

Multiple Choice

Q 78Q 78

When a 1.0-m length of metal wire is connected to a battery, a current of flows through it. What is the diameter of the wire? The resistivity of the metal is 2.24 × 10

^{-8}Ω ∙ m. A)12 μm B)6.0 μm C)24 μm D)2.2 μmFree

Multiple Choice

Q 79Q 79

The resistance of a 100-cm wire of cross sectional area 2 × is 400 Ω. What is the resistivity of the material from which this wire is made?
A)0.80 × Ω ∙ m
B)8.0 × Ω ∙ m
C)0.80 × Ω ∙ m
D)0.80 × Ω ∙ m
E)8.0 × Ωv

Free

Multiple Choice

Q 80Q 80

The resistivity of the material of a wire is 1.76 × 10

^{-8}Ω ∙ m. If the diameter of the wire is 2.00 mm and its length is 2.00 m, what is its resistance? A)112 Ω B)11.2 Ω C)1.12 Ω D)0.112 Ω E)0.0112 ΩFree

Multiple Choice

Q 81Q 81

The resistivity of a 1.0 m long copper wire is 1.72 × 10

^{-8}Ω ∙ m and its cross sectional area is 2.0 × 10^{-6}m^{2}. If the wire carries a current of 0.20 A, what is the voltage across the wire? A)17 mV B)0.90 mV C)1.7 mV D)10 mV E)90 mVFree

Multiple Choice

Q 82Q 82

How much current will flow through a length of metal wire with a radius of if it is connected to a power source supplying The resistivity of the metal is 1.68 × 10

^{-8}Ω ∙ m. A)0 A B)0 x 10^{8}A C)0 nA D)0 AFree

Multiple Choice

Q 83Q 83

When a potential difference is applied across a piece of wire made of metal A, a current flows. If the metal-A wire is replaced with a wire made of metal B having twice the diameter of the metal-A wire, how much current will flow through the metal-B wire? The lengths of both wires are the same, and the voltage difference remains unchanged. The resistivity of metal A is 1.68 × 10

^{-8}Ω ∙ m, and the resistivity of metal B is 1.59 × 10^{-8}Ω ∙ m. A)21 mA B)19 mA C)11 mA D)5.3 mAFree

Multiple Choice

Q 84Q 84

A tube of mercury with resistivity 9.84 × 10

^{-7}Ω ∙ m has a uniform electric field of 23 N/C inside the mercury. How much current is flowing in the tube, if the radius of the tube is 0.495 mm? A)18 A B)180 A C)29 A D)280 AFree

Multiple Choice

Q 85Q 85

The power rating of a 400-Ω resistor is 0.800 W.
(a)What is the maximum safe voltage across this resistor?
(b)What is the maximum current the resistor can safely draw?

Free

Essay

Q 86Q 86

A resistor operated at 120 V dc is rated at 1.40 kW.
(a)What is the normal operating current through the resistor?
(b)What is the resistance of the resistor?

Free

Essay

Q 87Q 87

A flashlight draws 0.133 A from a 3.0-V battery pack. In 2.0 minutes (a)how much charge flows from the battery, (b)how much energy does the battery supply, and (c)how many electrons have passed any point in the circuit every second?

Free

Essay

Q 88Q 88

An instrument is rated at 250 W if it is connected across a 120-V dc power supply.
(a)What current does it draw under normal operation?
(b)What is its resistance?
(c)How many kilowatt-hours does it use in a day if it is left on all the time?

Free

Essay

Q 89Q 89

A 200-W light bulb is connected across a 110-V dc power supply. What current will flow through this bulb?
A)0.90 A
B)0.36 A
C)0 A
D)0.60 A
E)1.8 A

Free

Multiple Choice

Q 90Q 90

A 100-W resistance heater is connected to a 110-V dc source. What current flows through the heater?
A)1.1 A
B)2.2 A
C)3.3 A
D)4.4 A
E)0.91 A

Free

Multiple Choice

Q 91Q 91

A 100-W light bulb is operated by a 110-V dc source. What is the resistance of this bulb?
A)100 Ω
B)8.0 × 10

^{-3}Ω C)6.0 × 10^{-3}Ω D)120 Ω E)240 ΩFree

Multiple Choice

Q 92Q 92

If the power rating of a 400-Ω resistor is 0.800 W, what is the maximum voltage that can safely be connected across the resistor?
A)110 V
B)17.9 V
C)170 V
D)1.80 V

Free

Multiple Choice

Q 93Q 93

If the power rating of a 400-Ω resistor is 0.80 W, what is the maximum current it can safely draw?
A)45 mA
B)18 mA
C)4.4 mA
D)2.0 mA
E)320 mA

Free

Multiple Choice

Q 94Q 94

A light bulb operating at a dc voltage of 120 V has a power rating of 60 W. How much current is flowing through this bulb?
A)1.5 A
B)2.5 A
C)0.50 A
D)2.0 A
E)1.0 A

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Multiple Choice

Q 95Q 95

A light bulb operating at a dc voltage of 120 V has a resistance of 200 Ω. How much power is dissipated in this bulb?
A)100 W
B)60 W
C)72 W
D)14 mW
E)7.2 W

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Multiple Choice

Q 96Q 96

The power rating of a 400-Ω resistor is 0.25 W. What is the maximum voltage you can safely connect across its ends?
A)10 V
B)20 V
C)30 V
D)40 V
E)50 V

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Multiple Choice

Q 97Q 97

When 5.00 A is flowing through an 10.0-Ω device, how much power is being dissipated in the device?
A)50.0 W
B)250 W
C)500 W
D)2.50 kW

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Multiple Choice

Q 98Q 98

A resistance heater is rated at 1200 W when operating at 110 V dc. What current will it draw?
A)0.090 A
B)1.0 A
C)11 A
D)12 A

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Multiple Choice

Q 99Q 99

A 150-W light bulb is designed to operate at 110 V dc. How much current does it draw?
A)0.73 A
B)1.4 A
C)2.0 A
D)15 A

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Multiple Choice

Q 100Q 100

What is the resistance of a 0.100-kW light bulb designed to be used in a 120-V circuit dc?
A)12.0 Ω
B)144 Ω
C)1.2 Ω
D)0.83 Ω

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Multiple Choice

Q 101Q 101

A toaster is rated at 800 W when operating at 120 V dc. What is the resistance of its heating element?
A)16 Ω
B)18 Ω
C)6.7 Ω
D)0.15 Ω

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Multiple Choice

Q 102Q 102

A 200-Ω resistor is rated at 1/4 W. What is the maximum current it can safely draw?
A)0.035 A
B)0.35 A
C)50 A
D)0.25 A

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Multiple Choice

Q 103Q 103

A 25-W soldering iron runs on 110 V dc. What is its resistance?
A)0.0020 Ω
B)4.4 Ω
C)0.48 kΩ
D)2.8 kΩ

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Multiple Choice

Q 104Q 104

How much does it cost to operate a 25-W soldering iron for 8.0 hours if energy costs 8.0¢/kWh?
A)$1.50
B)25¢
C)16¢
D)1.6¢

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Multiple Choice

Q 105Q 105

How much energy does a 100-W light bulb use in 8.0 hours?
A)0.0080 kWh
B)0.80 kWh
C)13 kWh
D)800 kWh

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Multiple Choice

Q 106Q 106

A 1500-W heater is connected to a 120-V line for 2.0 hours. How much heat energy is produced?
A)1.5 kJ
B)3.0 kJ
C)0.18 MJ
D)11 MJ

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Multiple Choice

Q 107Q 107

A battery is rated at 12 V and 160 A-h. How much energy does this battery store?
A)1.9 kJ
B)6.0 kJ
C)1.9 MJ
D)6.9 MJ

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Multiple Choice

Q 108Q 108

An electronic component with a 17-Ω resistor is rated for use at power levels not exceeding How much current can safely flow through the component?
A)0.91 A
B)1.21 A
C)238 A
D)0.22 A

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Multiple Choice

Q 109Q 109

A 100-W driveway light bulb is on 10 hours per day. If the power company charges 10¢ for each kilowatt-hour of electricity used, estimate the yearly cost to operate the bulb if it is used every day for a 365-day year.
A)$3.65
B)$7.30
C)$37
D)$73

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Multiple Choice

Q 110Q 110

A 400-W computer (including its monitor)is turned on for 8.0 hours per day. If electricity costs 10¢ per kWh, how much does it cost to run the computer annually for a 365-day year?
A)$120
B)$1200
C)$15
D)$150

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Multiple Choice

Q 111Q 111

The nichrome heating element in an electric drier operates on 240 V and generates heat at the rate of 2.0 kW. The heating element shorts out and, in repairing it, the repairman shortens the nichrome wire by 10%. (Assume the temperature is unchanged. In reality, the resistivity of the wire will depend on its temperature.)What effect will the repair have on the power dissipated in the heating element?
A)The power is still 2.0 kW.
B)The power increases to 2.2 kW.
C)The power decreases to 1.8 kW.
D)None of the given answers is correct.

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Multiple Choice

Q 112Q 112

When a 14.0-A current flows through an 8.00-Ω device for 24.0 hours, how much does this cost if energy costs $0.0900 per kW ∙ h?
A)$0.24
B)$1.04
C)$2.16
D)$3.39

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Multiple Choice

Q 113Q 113

A 9.0-V battery costs $1.49 and will run a portable CD player for 6.0 hours before running down and needing to be replaced. If this battery supplies a current of 25 mA to the player, what is the cost of the energy provided by the battery in dollars per kWh?
A)$11/kWh
B)$110/kWh
C)$1100/kWh
D)$11,000/kWh

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Multiple Choice

Q 114Q 114

A 200-Ω resistor is rated at 1/4 W. What is the maximum voltage that can safely be connected across it?
A)0.71 V
B)7.1 V
C)50 V
D)0.25 V

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Multiple Choice

Q 115Q 115

A simple circuit has a total resistance of 30 Ω. If a 2.0-A current is maintained in this circuit, how much energy is dissipated in this circuit in 4.0 seconds?
A)24 J
B)4.8 J
C)48 J
D)480 J
E)6.0 J

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Multiple Choice

Q 116Q 116

The resistivity of gold is at a temperature of 20°C. A gold wire, 1.8 mm in diameter and 14 cm long, carries a current of 480 mA. What power is dissipated in this wire at 20°C?
A)0.31 mW
B)0.077

_{ }mW C)0.14 mW D)0.19 mW E)0.25 mWFree

Multiple Choice

Q 117Q 117

A 120-Ω laboratory resistor is rated at 0.25 W. How much current can safely flow through the resistor?
A)30 A
B)2.1 mA
C)22 mA
D)46 mA

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Multiple Choice

Q 118Q 118

The voltage drop across a metal bar is while a current of flows through it. How much power does this bar dissipate?
A)50 mW
B)500 μW
C)2.5 kW
D)0.50 kW

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Multiple Choice

Q 119Q 119

A battery is rated such that it provides of power at when fully charged. How much current can it deliver?
A)0.11 mA
B)81 kA
C)0.33 mA
D)9.1 kA

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Multiple Choice

Q 120Q 120

A device with a resistance of is connected to a battery. How much power does the device use?
A)0.50 mW
B)20,000 kW
C)0.050 mW
D)2000 kW

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Multiple Choice

Q 121Q 121

A 6.0-V battery that can store of energy is connected to a resistor. How much charge must flow between the battery's terminals to completely drain the battery if it is fully charged? Assume that the voltage of the battery remains the same until it is totally drained.
A)83 C
B)0.010 C
C)3000 C
D)0.07 C

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Multiple Choice

Q 122Q 122

The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10

^{-6}Ω ∙ m. The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation? A)370 W B)360 W C)380 W D)400 W E)410 WFree

Multiple Choice

Q 123Q 123

A battery supplies 6.0 mA to a 12-Ω resistor for 1.5 h. How much electric energy does this resistor dissipate in this time?

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Essay

Q 124Q 124

A 5.0-V battery storing 43.0 kJ of energy supplies of current to a circuit. How much energy does the battery have left after powering the circuit for
A)16 kJ
B)27 kJ
C)43 kJ
D)41 kJ

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Multiple Choice