Deck 5: Parallel Circuits

Question 1

If a 500, 1200 $\Omega$ and 10 $\mathrm { k } \Omega$ resistor are connected in parallel across a 25 V source, how much current flows through the 1200 $\Omega$ resistor?

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

Answer 1

20.8 mA

Question 2

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

Answer 2

True

Question 3

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

Answer 3

False

Question 4

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

Question 5

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

Question 6

If I_R1=0.065 mA and I_R2=0.098 mA in a two branch parallel circuit,I_T=0.163mA

Question 7

If a 2.2 $k \Omega$ resistor and a 3.3 $\mathrm { k } \Omega$ resistor are connected in parallel, RT equals________

A) 2.2 $\mathrm { k } \Omega$
B) 3.3 $\mathrm { k } \Omega$
C) greater than 2.2 $\mathrm { k } \Omega$
D) less than 2.2 $\mathrm { k } \Omega$

Question 8

Accurate troubleshooting of a parallel circuit cannot be performedW ith a voltmeter.

Question 9

If twelve 1.5 $\mathrm { M } \Omega$ resistors are connected in parallel across 50 V, R_T equals______

A) 0.125 $\mathrm { M } \Omega$
B) 1 $\mathrm { M } \Omega$
C) 1.25 $\mathrm { M } \Omega$
D) 1.5 $\mathrm { M } \Omega$

Question 10

IT equals 0.1 mA in a 3-branch parallel circuit. If I₁=0.022 mA and I₂=0.007 mA, I₃=?

A) 0.029 mA
B) 0.071 mA
C) 0.213 mA
D) 0.142 mA

Question 11

Kirchhoffʹs Current Law states that the sum of the currents into a junction must equal the sum of the currents out of that junction.

Question 12

If I_R1=75 mA and I_R2=12.7 mA in a two branch parallel circuit, I_T=85.7 mA .

Question 13

If a 5.5 $\mathrm { k } \Omega$ , 22 $\mathrm { k } \Omega$ and 500 $\Omega$ resistor are connected in parallel, what is RT ?

A) 28.1 $\mathrm { k } \Omega$
B) 449 $\Omega$
C) 330 $\Omega$
D) 27.6 $\mathrm { k } \Omega$

Question 14

In a three-resistor parallel circuit, R₁=0.22 $M \Omega$ and R₂=1 $M \Omega$ . If R T=0.1166 $M \Omega$ , then what is the value of R₃ ?

A) 1.34 M $\Omega$
B) 0.134 M $\Omega$
C) 0.33 M $\Omega$
D) 13,400 $\Omega$

Question 15

Measurement of total current is accomplishedW ith the ammeter in seriesW ith the source voltage

Question 16

If a 1 $\mathrm { M } \Omega$ resistor, 0.47 $\mathrm { M } \Omega$ resistor and 0.5 $\mathrm { M } \Omega$ resistor are connected in parallel across an 18 V source, what is the total current if the 1 $\mathrm { M } \Omega$ resistor opens?

A) 74.3 $\mu A$
B) 74.3 mA
C) 92.3 mA
D) 92.3 $\mu A$

Question 17

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

Question 18

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

Question 19

P_R1=0.25 W and P_R2=1.2 W in a parallel circuit. The total power dissipated is 1.25 W .

Question 20

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

Question 21

R_T=330 and R₁=470 $\Omega$ in a two-branch parallel circuit. What is the value of R₂?

A) 1108 $\Omega$
B) 110 $\Omega$
C) 194 $\Omega$
D) 770 $\Omega$

Question 22

If a 2.2 $k \Omega$ resistor, 10 $\mathrm { k } \Omega$ resistor and 1.2 $\mathrm { k } \Omega$ resistor are connected in parallel, the total resistance equals______

A) 721 $\Omega$
B) 13.4 $\mathrm { k } \Omega$
C) 1.2 $\mathrm { k } \Omega$
D) 2.27 $\mathrm { k } \Omega$

Question 23

If a 4.7 $\mathrm { k } \Omega$ resistor and 2.2 $\mathrm { k } \Omega$ resistor are connected in parallel, the total resistance is____

A) 4700 $\Omega$
B) 2200 $\Omega$
C) greater than 2200 $\Omega$
D) less than 2200 $\Omega$

Question 24

If 5 A and 3A enter a junction from two separate paths, how much current flows out of the junction?

A) 3 A
B) 8 A
C) 2 A
D) the larger of the two

Question 25

If you measure a lower than normal total current in a parallel circuit, ________.

A)all of the resistors are opened
B)a resistor opened
C)the power supply is off
D)a resistor shorted

Question 26

If three 22 $\mathrm { k } \Omega$ resistors are connected in parallel across a 10 V source, P_T equals________

A) 22.6 m W
B) 4.5 m W
C) 13.6 m W
D) 18.1 m W

Question 27

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) 0 A
B) 30 mA
C) 13.33 mA
D) 10 mA

Question 28

A two-branch parallel circuit contains these values: R₁=1200 , I_T=0.005 mA, I₂=0.003 mA . What is the value of V_R1 ?

A) 2.4 m V
B) 3.6 m V
C) 6 mV
D) 18 mV

Question 29

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

A)decreases, increases
B)decreases, decreases
C)increases, increases
D)increases, decreases

Question 30

The current through any branch of a parallel circuit_________

A) is directly proportional to the branch resistance
B) depends on the power rating of the resistor
C) depends only on the circuit voltage
D) is inversely proportional to the branch resistance

Question 31

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

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

Question 32

If the power dissipation in each of four parallel branches is 1 W, P_T equals_______

A) 1 W
B) 4 W
C) 0 W
D) 0.25 W

Question 33

If you Want to measure a load voltage With a DVM, connect the meter ________.

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

Question 34

If there is 100 mA of current flowing into a three-branch parallel circuit and two of the branch currents are 40 mA and 20 mA , the third branch current is________

A) 20 mA
B) 40 mA
C) 60 mA
D) 160 mA

Question 35

If four 100W lamps are connected in parallel across a 120 V source,W hat is the total current?

A)33.3 A
B)833 mA
C)8.33 A
D)3.33 A

Question 36

If a 330 $\Omega$ resistor, 270 $\Omega$ resistor and 68 $\Omega$ resistor are connected in parallel, what is the approximate value for R_T?

A) 668 $\Omega$
B) 68 $\Omega$
C) 22 $\Omega$
D) 47 $\Omega$

Question 37

If a 470 $\Omega$ resistor,680 $\Omega$ resistor and 830 $\Omega$ resistor are connected in parallel, the total resistance equals_______

A) 1980 $\Omega$
B) 1150 $\Omega$
C) 208 $\Omega$
D) 1510 $\Omega$

Question 38

A formula that applies to a two-branch parallel circuit is_______

A) $\mathrm { RT } _ { \mathrm { T } } = \mathrm { R } _ { 1 } + \mathrm { R } _ { 2 }$
B) $\mathrm { R_T } = \mathrm { V } 1 \div \mathrm { R } _ { 2 }$
C) $\mathrm R_T= \mathrm { IR } _1 + \mathrm { IR } _2$
D) $\mathrm { V_T } = \mathrm { VR } _1 + \mathrm { VR }_ 2$

Question 39

If a $k \Omega$ resistor, a 3.3 $k \Omega$ resistor and a 5.43 $k \Omega$ resistor are connected in parallel across a 50V source, what is the current through the 5.43 $k \Omega$ resistor?

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

Question 40

As additional branch resistors are connected in a parallel circuit,_________

A) I_T decreases and R_T increases
B) I_T increases and R_T increases
C) I_T decreases and R_T decreases
D) I_T increases and R_T decreases

Question 41

If one resistor opens in a parallel circuit, the total current________

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

Question 42

A short in one branch of a parallel circuit results in:

A)increased circuit resistance.
B)decreased power consumption.
C)increasedVoltage drops in the remaining branches.
D)increased current flow.

Question 43

As resistors are disconnected from a parallel circuit,______

A) I_T increases and R_T decreases
B) I_T decreases and R _T decreases
C) I_T increases and R_T increases
D) I_T decreases and R_T increases

Question 44

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

A) 376
B) 5.88
C) 6.71
D) 4.7

Question 45

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

A) 16.8
B) 3.2
C) 12
D) 21.3

Question 46

To measure the current through one branch of a parallel circuit, the meter is connected________

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

Question 47

A 5.2 $\mathrm { M } \Omega$ resistor, 1.2 $\mathrm { M } \Omega$ resistor and 1 $\mathrm { M } \Omega$ resistor are connected in parallel across a 15 V source. What is the total current if the 1.2 $\mathrm { M } \Omega$
resistor opens?

A) 2.88 $\mu \mathrm { A }$
B) 12.5 $\mu A$
C) 2.41 $\mu \mathrm { A }$
D) 17.9 $\mu A$

Question 48

Refer to Figure 5-1. The voltage across R₂ is 0 V. What is most likely the problem?

A) R₂ open
B) fuse open
C) R₁ open
D) none of the above

Question 49

In a three-branch parallel circuit, R₁=1.2 $\mathrm { M } \Omega$ , R₂=1 $\mathrm { M } \Omega$ and R_T=0.5 $\mathrm { M } \Omega$ . Calculate R₃ .

A) 6 $\mathrm { M } \Omega$
B) 2 $\mathrm { M } \Omega$
C) 7.7 $\mathrm { M } \Omega$
D) 1.7 $\mathrm { M } \Omega$

Question 50

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) R₃ open
B) R₁ open
C) R₂ open
D) This is normal.

Question 51

An open in one branch of a parallel circuit results in:

A)decreased or reduced current flow.
B)decreased power consumption.
C)increased circuit resistance.
D)all of these.

Question 52

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) 2.4 mA
B) 8.7 mA
C) 7.2 mA
D) 0.3 mA

Question 53

If three 4.7 resistors are connected in parallel across a 12 V source, what is the value of P_T ?

A) 141 mW
B) 14.1 mW
C) 91.9 mW
D) 1.41 W

Question 54

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) one of the resistors has shorted
C) one resistor has opened
D) the power supply is off

Question 55

The most popular application for a parallel circuit in electronics is as a:

A)voltage divider.
B)resistance divider.
C)current divider.
D)power divider.

Question 56

If three 75 W lamps are connected in parallel across a 125 V source, I_T equals_______

A) 1.8 A
B) 180 mA
C) 18 A
D) 18 mA

Question 57

Refer to Figure 5-1. To accurately measure the total current for this circuit, how must the ammeter be connected?

A) between the negative terminal and the supply and ground
B) between R1 and the fuse
C) between the positive terminal and the fuse
D) either A or C

Question 58

The power dissipated by any branch of a parallel circuit_____

A) depends on the power rating of the resistor
B) only depends on the circuit voltage
C) depends on the voltage and value of the resistor
D) only depends on the total current

Question 59

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

A)
B)
C)
D)

Question 60

In a parallel circuit, the largest amount of power is dissipated by:

A)the first resistor.
B)the largest resistor.
C)the smallest resistor.
D)any resistor, since theVoltage is the same across each of the branch circuits.

Question 61

$$\text { Figure } 5 < 1$$

-Refer to Figure 5-1. The fuse in this circuit is rated at 100 mA . Would the fuse blow if an additional 1 $\mathrm { k } \Omega$ were placed in parallel with R5?

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

Question 62

Refer to Figure 5-1. What is the power dissipation of R3?

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