# Quiz 5: Parallel Circuits

Physics & Astronomy

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True False

False

Q 2Q 2

The total resistance of four resistors in parallel is always less than the smallest resistance.

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True False

True

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True False

True

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True False

Q 5Q 5

The total power dissipated by a parallel circuit can be found by adding the individual powers.

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True False

Q 6Q 6

Kirchhoff's Current Law states that the sum of the currents into a junction must equal the sum of the currents out of that junction.

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True False

Q 7Q 7

The total resistance of three parallel resistors equals the sum of the individual resistor values.

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True False

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True False

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True False

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True False

Q 11Q 11

Measurement of total current is accomplished with the ammeter in series with the source voltage.

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True False

Q 12Q 12

A parallel circuit can be easily identified because only one end of each component is connected to each other.

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True False

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True False

Q 14Q 14

Total power for a parallel circuit can be determined by the same method as a series circuit.

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True False

Q 15Q 15

If a 5.5 kâ–², 22 kâ–² and 500 â–² resistor are connected in parallel, what is RT?
A)449 â–²
B)28.1 kâ–²
C)330 â–²
D)27.6 kâ–²

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Multiple Choice

Q 16Q 16

If a 500 â–², 1200 â–² and 10 kâ–² resistor are connected in parallel across a 25 V source, how much current flows through the 1200 â–² resistor?
A)20.8 mA
B)50 mA
C)2.4 mA
D)2.5 mA

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Multiple Choice

Q 17Q 17

If a 2.2 kâ–² resistor and a 3.3 kâ–² resistor are connected in parallel, RT equals .
A)3.3 kâ–²
B)2.2 kâ–²
C)greater than 2.2 kâ–²
D)less than 2.2 kâ–²

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Multiple Choice

Q 18Q 18

In a three -resistor parallel circuit, R1 = 0.22 Mâ–² and R2 = 1 Mâ–². If RT = 0.1166 Mâ–², then what is the value of R3?
A)1.34 M â–²
B)0.134 M â–²
C)0.33 M â–²
D)13,400 â–²

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Multiple Choice

Q 19Q 19

If a 1 Mâ–² resistor, 0.47 Mâ–² resistor and 0.5 Mâ–² resistor are connected in parallel across an 18V source, what is the total current if the 1 Mâ–² resistor opens?
A)74.3 ÂµA
B)92.3 ÂµA
C)74.3 mA
D)92.3 mA

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Multiple Choice

Q 20Q 20

If twelve 1.5 Mâ–² resistors are connected in parallel across 50 V, RT equals .
A)1.5 M â–²
B)1 Mâ–²
C)0.125 Mâ–²
D)1.25 Mâ–²

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Multiple Choice

Q 21Q 21

IT equals 0.1 mA in a 3 -branch parallel circuit. If I1 = 0.022 mA and I2 = 0.007 mA, I3 = ?
A)0.071 mA
B)0.142 mA
C)0.029 mA
D)0.213 mA

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Multiple Choice

Q 22Q 22

If one resistor opens in a parallel circuit, the total circuit resistance and the total circuit current .
A)increases, increases
B)decreases, decreases
C)increases, decreases
D)decreases, increases

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Multiple Choice

Q 23Q 23

If three 22 kâ–² resistors are connected in parallel across a 10 V source, PT equals .
A)22.6 m W
B)18.1 m W
C)4.5 m W
D)13.6 m W

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Multiple Choice

Q 24Q 24

If one resistor shorts in a parallel circuit, the total current .
A)increases
B)decreases
C)equals 0 A
D)decreases momentarily, then returns to the original value

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Multiple Choice

Q 25Q 25

If four 100 W lamps are connected in parallel across a 120 V source, what is the total current?
A)833 mA
B)33.3 A
C)8.33 A
D)3.33 A

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Multiple Choice

Q 26Q 26

If you measure a lower than normal total current in a parallel circuit, .
A)the power supply is off
B)a resistor shorted
C)all of the resistors are opened
D)a resistor opened

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Multiple Choice

Q 27Q 27

A formula that applies to a two -branch parallel circuit is .
A)RT = R1 + R2
B)IT = IR1 + IR2
C)RT = V1 Ã· R2
D)VT = VR1 + VR2

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Multiple Choice

Q 28Q 28

The current through any branch of a parallel circuit .
A)is directly proportional to the branch resistance
B)depends only on the circuit voltage
C)is inversely proportional to the branch resistance
D)depends on the power rating of the resistor

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Multiple Choice

Q 29Q 29

If you want to measure a load voltage with a DVM, connect the meter .
A)in parallel with the load
A)in series with the source
B)across the source
D)in series with the load

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Multiple Choice

Q 30Q 30

The total resistance of a three -branch parallel circuit is 76.92 â–². If R1 = 100 â–² and R2 = 500 â–², what is the value of R3?
A)1850 â–²
B)1000 â–²
B)More information is needed to calculate R3.
C)140 â–²

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Multiple Choice

Q 31Q 31

A two -branch parallel circuit contains these values: R1 = 1200 â–², IT = 0.005 mA, I2 = 0.003 mA. What is the value of VR1?
A)18 m V
B)3.6 m V
C)6 m V
D)2.4 m V

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Multiple Choice

Q 32Q 32

As additional branch resistors are connected in a parallel circuit, .
A)IT increases and RT increases
B)IT increases and RT decreases
C)IT decreases and RT increases
D)IT decreases and RT decreases

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Multiple Choice

Q 33Q 33

If a 4.7 kâ–² resistor, a 3.3 kâ–² resistor and a 5.43 kâ–² resistor are connected in parallel across a 50 V source, what is the current through the 5.43 kâ–² resistor?
A)9.21 mA
B)4.72 mA
C)15.15 mA
D)10.64 mA

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Multiple Choice

Q 34Q 34

RT = 330 â–² and R1 = 470 â–² in a two -branch parallel circuit. What is the value of R2?
A)110 â–²
B)770 â–²
C)1108 â–²
D)194 â–²

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Multiple Choice

Q 35Q 35

If a 330 â–² resistor, 270 â–² resistor and 68 â–² resistor are connected in parallel, what is the approximate value for RT?
A)668 â–²
B)68 â–²
C)47 â–²
D)22 â–²

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Multiple Choice

Q 36Q 36

If 5 A and 3 A enter a junction from two separate paths, how much current flows out of the junction?
A)2 A
B)8 A
C)3 A
D)the larger of the two

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Multiple Choice

Q 37Q 37

Each branch in a four -branch parallel circuit carries 10 mA. If one of the branches opens, then the current in each of the other three branches equals .
A)30 mA
B)10 mA
C)0 A
D)13.33 mA

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Multiple Choice

Q 38Q 38

If there is 100 mA of current flowing into a three -branch parallel circuit and two of the branc currents are 40 mA and 20 mA, the third branch current is .
A)40 mA
B)20 mA
C)160 mA
D)60 mA

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Multiple Choice

Q 39Q 39

If the power dissipation in each of four parallel branches is 1 W, PT equals .
A)0 W
B)4 W
C)1 W
D)0.25 W

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Multiple Choice

Q 40Q 40

If a 2.2 kâ–² resistor, 10 kâ–² resistor and 1.2 kâ–² resistor are connected in parallel, the total resistance equals .
A)1.2 kâ–²
B)2.27 kâ–²
C)721 â–²
D)13.4 kâ–²

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Multiple Choice

Q 41Q 41

If a 470 â–² resistor, 680 â–² resistor and 830 â–² resistor are connected in parallel, the total resistance equals .
A)1150 â–²
B)1510 â–²
C)1980 â–²
D)208 â–²

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Multiple Choice

Q 42Q 42

If a 4.7 kâ–² resistor and 2.2 kâ–² resistor are connected in parallel, the total resistance is .
A)4700 â–²
B)2200 â–²
C)greater than 2200 â–²
D)less than 2200 â–²

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Multiple Choice

Q 43Q 43

In a three -branch parallel circuit, R1 = 1.2 Mâ–², R2 = 1 Mâ–² and RT = 0.5 Mâ–². Calculate R3.
A)7.7 Mâ–²
B)2 Mâ–²
C)1.7 Mâ–²
D)6 Mâ–²

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Multiple Choice

Q 44Q 44

A 5.2 Mâ–² resistor, 1.2 Mâ–² resistor and 1 Mâ–² resistor are connected in parallel across a 15 V source. What is the total current if the 1.2 Mâ–² resistor opens?
A)17.9 ÂµA
B)12.5 ÂµA
C)2.88 ÂµA
D)2.41 ÂµA

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Multiple Choice

Q 45Q 45

If eight 47 kâ–² resistors are connected in parallel across a 25 V source, RT equals .
A)6.71 kâ–²
B)5.88 kâ–²
C)376 kâ–²
D)4.7 kâ–²

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Multiple Choice

Q 46Q 46

A three -branch parallel circuit carries a total current of 1.2 mA. If I1 = 0.2 mA and I2 = 0.7 mA, then what is the value of I3?
A)7.2 mA
B)0.3 mA
C)8.7 mA
D)2.4 mA

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Multiple Choice

Q 47Q 47

If three 4.7 kâ–² resistors are connected in parallel across a 12 V source, what is the value of PT?
A)91.9 mW
B)1.41 W
C)141 mW
D)14.1 mW

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Multiple Choice

Q 48Q 48

If one resistor opens in a parallel circuit, the total current .
A)varies wildly
B)decreases
C)remains unchanged
D)increases

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Multiple Choice

Q 49Q 49

If three 75 W lamps are connected in parallel across a 125 V source, IT equals .
A)18 mA
B)18 A
C)1.8 A
D)180 mA

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Multiple Choice

Q 50Q 50

If the total current equals 0 A in a four -branch parallel circuit, the trouble is that .
A)three of the resistors have opened
B)the power supply is off
C)one of the resistors has shorted
D)one resistor has opened

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Multiple Choice

Q 51Q 51

The power dissipated by any branch of a parallel circuit .
A)only depends on the total current
B)depends on the power rating of the resistor
C)only depends on the circuit voltage
D)depends on the voltage and value of the resistor

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Multiple Choice

Q 52Q 52

To measure the current through one branch of a parallel circuit, the meter is connected .
A)in series with the source
B)in series with the branch resistor
C)in parallel with the branch resistor
D)across the source

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Multiple Choice

Q 53Q 53

If the RT = 6.8 kâ–² and R1 = 10 kâ–² in a two -branch parallel circuit, what is the value of R2?
A)3.2 kâ–²
B)12 kâ–²
C)21.3 kâ–²
D)16.8 kâ–²

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Multiple Choice

Q 54Q 54

As resistors are disconnected from a parallel circuit, .
A)IT increases and RT increases
B)IT increases and RT decreases
C)IT decreases and RT increases
D)IT decreases and RT decreases

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Multiple Choice

Q 55Q 55

The most popular application for a parallel circuit in electronics is as a:
A)current divider.
B)resistance divider.
C)power divider.
D)voltage divider.

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Multiple Choice

Q 56Q 56

In a parallel circuit, total power PT is calculated as:
A)P1 Ã— P2 Ã— P3 Ã— etc.
B)1/P1 + 1/P2 + 1/P3 + etc.
C)P1 Ã· P2 Ã· P3 Ã· etc.
D)P1 + P2 + P3 + etc.

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Multiple Choice

Q 57Q 57

In a parallel circuit, the largest amount of power is dissipated by:
A)the smallest resistor.
B)the first resistor.
C)the largest resistor.
D)any resistor, since the voltage is the same across each of the branch circuits.

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Multiple Choice

Q 58Q 58

An open in one branch of a parallel circuit results in:
A)decreased power consumption.
B)increased circuit resistance.
C)decreased or reduced current flow.
D)all of these.

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Multiple Choice

Q 59Q 59

A short in one branch of a parallel circuit results in:
A)increased voltage drops in the remaining branches.
B)increased circuit resistance.
C)decreased power consumption.
D)increased current flow.

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Multiple Choice

Q 60Q 60

Figure 5 -1
-Refer to Figure 5 -1. The voltage across R2 is 0 V. What is most likely the problem?
A)R1 open
B)fuse open
C)R2 open
D)none of the above

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Multiple Choice

Q 61Q 61

Figure 5 -1
-Refer to Figure 5 -1. To accurately measure the total current for this circuit, how must the ammeter be connected?
A)between the positive terminal and the fuse
B)between R1 and the fuse
C)between the negative terminal and the supply and ground
D)either A or C

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Multiple Choice

Q 62Q 62

Figure 5 -1
-Refer to Figure 5 -1. The total current for this circuit is measured and the ammeter reads 57.8 mA. What is the problem, if any?
A)R1 open
B)R3 open
C)R2 open
D)This is normal.

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Multiple Choice

Q 63Q 63

Figure 5 -1
-Refer to Figure 5 -1. The fuse in this circuit is rated at 100 mA. Would the fuse blow if an additional 1 kâ–² were placed in parallel with R5?
A)yes
B)no
C)Fuse has nothing to do with this part of the circuit.

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Multiple Choice

Q 64Q 64

Figure 5 -1
-Refer to Figure 5 -1. What is the power dissipation of R3?
A)11.4 mW
B)568 mW
C)25 mW
D)284 mW

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Multiple Choice

Q 65Q 65

The maximum current that an analog meter movement can handle is called
A)full -load scale current
B)full -scale deflection current
C)maximum surge current
D)maximum scale current

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Multiple Choice

Q 66Q 66

A thermal image is also known as a(n)
A)radiometric image
B)hot shot
C)infrared projection
D)all of the above

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Multiple Choice