Deck 5: Parallel Circuits

Question 1

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

Answer 1

True

Question 2

If a 5.5 kΩ, 22 kΩ and 500 Ω resistor are connected in parallel, what is RT?

A)449 Ω
B)28.1 kΩ
C)330 Ω
D)27.6 kΩ

Answer 2

449 Ω

Question 3

If a 2.2 kΩ resistor and a 3.3 kΩ resistor are connected in parallel, RT equals .

A)3.3 kΩ
B)2.2 kΩ
C)greater than 2.2 kΩ
D)less than 2.2 kΩ

Answer 3

less than 2.2 kΩ

Question 4

If three equal resistors are connected in parallel across 12 V, each resistor drops 4 V.

Question 5

If one branch of a parallel circuit shorts, the total resistance decreases.

Question 6

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

Question 7

If twelve 1.5 MΩ resistors are connected in parallel across 50 V, RT equals .

A)1.5 M Ω
B)1 MΩ
C)0.125 MΩ
D)1.25 MΩ

Question 8

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

Question 9

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

Question 10

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.

Question 11

If IR1 = 0.065 mA and IR2 = 0.098 mA in a two branch parallel circuit, IT = 0.163 mA.

Question 12

In a three -resistor parallel circuit, R1 = 0.22 MΩ and R2 = 1 MΩ. If RT = 0.1166 MΩ, then what is the value of R3?

A)1.34 M Ω
B)0.134 M Ω
C)0.33 M Ω
D)13,400 Ω

Question 13

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

Question 14

PR1 = 0.25 W and PR2 = 1.2 W in a parallel circuit. The total power dissipated is 1.25 W.

Question 15

If IR1 = 75 mA and IR2 = 12.7 mA in a two branch parallel circuit, IT = 85.7 mA.

Question 16

If a 1 MΩ resistor, 0.47 MΩ resistor and 0.5 MΩ resistor are connected in parallel across an 18V source, what is the total current if the 1 MΩ resistor opens?

A)74.3 µA
B)92.3 µA
C)74.3 mA
D)92.3 mA

Question 17

Accurate troubleshooting of a parallel circuit cannot be performed with a voltmeter.

Question 18

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

Question 19

If a 500 Ω, 1200 Ω and 10 kΩ resistor are connected in parallel across a 25 V source, how much current flows through the 1200 Ω resistor?

A)20.8 mA
B)50 mA
C)2.4 mA
D)2.5 mA

Question 20

If one branch of a parallel circuit opens, the total resistance decreases.

Question 21

If three 22 kΩ 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

Question 22

If a 2.2 kΩ resistor, 10 kΩ resistor and 1.2 kΩ resistor are connected in parallel, the total resistance equals .

A)1.2 kΩ
B)2.27 kΩ
C)721 Ω
D)13.4 kΩ

Question 23

If you want to measure a load voltage with a DVM, connect the meter .

A)in parallel with the load
B)across the source
C)in series with the source
D)in series with the load

Question 24

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

Question 25

A formula that applies to a two -branch parallel circuit is .

A)RT = R1 + R2
B)IT = IR1 + IR2
C)RT = V1 ÷ R2
D)VT = VR1 + VR2

Question 26

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

Question 27

If a 4.7 kΩ resistor, a 3.3 kΩ resistor and a 5.43 kΩ resistor are connected in parallel across a 50 V source, what is the current through the 5.43 kΩ resistor?

A)9.21 mA
B)4.72 mA
C)15.15 mA
D)10.64 mA

Question 28

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

Question 29

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

Question 30

If a 330 Ω resistor, 270 Ω resistor and 68 Ω resistor are connected in parallel, what is the approximate value for RT?

A)668 Ω
B)68 Ω
C)47 Ω
D)22 Ω

Question 31

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

Question 32

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

Question 33

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

Question 34

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

Question 35

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

Question 36

A two -branch parallel circuit contains these values: R1 = 1200 Ω, 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

Question 37

The total resistance of a three -branch parallel circuit is 76.92 Ω. If R1 = 100 Ω and R2 = 500 Ω, what is the value of R3?

A)1850 Ω
B)1000 Ω
C)140 Ω
D)More information is needed to calculate R3.

Question 38

RT = 330 Ω and R1 = 470 Ω in a two -branch parallel circuit. What is the value of R2?

A)110 Ω
B)770 Ω
C)1108 Ω
D)194 Ω

Question 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

Question 40

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

Question 41

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.

Question 42

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.

Question 43

If eight 47 kΩ resistors are connected in parallel across a 25 V source, RT equals .

A)6.71 kΩ
B)5.88 kΩ
C)376 kΩ
D)4.7 kΩ

Question 44

If one resistor opens in a parallel circuit, the total current .

A)varies wildly
B)decreases
C)remains unchanged
D)increases

Question 45

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

Question 46

If a 470 Ω resistor, 680 Ω resistor and 830 Ω resistor are connected in parallel, the total resistance equals .

A)1150 Ω
B)1510 Ω
C)1980 Ω
D)208 Ω

Question 47

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.

Question 48

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

Question 49

In a parallel circuit, total power PT is calculated as:

A)P1 × P2 × P3 × etc.
B)1/P1 + 1/P2 + 1/P3 + etc.
C)P1 ÷ P2 ÷ P3 ÷ etc.
D)P1 + P2 + P3 + etc.

Question 50

A 5.2 MΩ resistor, 1.2 MΩ resistor and 1 MΩ resistor are connected in parallel across a 15 V source. What is the total current if the 1.2 MΩ resistor opens?

A)17.9 µA
B)12.5 µA
C)2.88 µA
D)2.41 µA

Question 51

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

Question 52

If the RT = 6.8 kΩ and R1 = 10 kΩ in a two -branch parallel circuit, what is the value of R2?

A)3.2 kΩ
B)12 kΩ
C)21.3 kΩ
D)16.8 kΩ

Question 53

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

Question 54

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.

Question 55

In a three -branch parallel circuit, R1 = 1.2 MΩ, R2 = 1 MΩ and RT = 0.5 MΩ. Calculate R3.

A)7.7 MΩ
B)2 MΩ
C)1.7 MΩ
D)6 MΩ

Question 56

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

Question 57

If a 4.7 kΩ resistor and 2.2 kΩ resistor are connected in parallel, the total resistance is .

A)4700 Ω
B)2200 Ω
C)greater than 2200 Ω
D)less than 2200 Ω

Question 58

If three 4.7 kΩ 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

Question 59

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

Question 60

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

Question 61

The fuse in this circuit is rated at 100 mA. Would the fuse blow if an additional 1 kΩ were placed in parallel with R5?

A)yes
B)no
C)Fuse has nothing to do with this part of the circuit.

Question 62

What is the power dissipation of R3?

A)11.4 mW
B)568 mW
C)25 mW
D)284 mW

Question 63

A thermal image is also known as a(n)

A)radiometric image
B)hot shot
C)infrared projection
D)all of the above

Question 64

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.

Question 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

Question 66

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