Deck 4: Energy and Power

Question 1

Calculate in Figure

A)24 V
B)16 V
C)56 V
D)112 V

Answer 1

56 V

Question 2

If a 1/4 W resistor and a 1/2 W resistor are wired in series, they can safely dissipate 3/4 W.

Answer 2

False

Question 3

The total power dissipated in a series circuit equals the sum of the individual powers.

Answer 3

True

Question 4

Calculating current for a series resistor circuit can be accomplished with a measured voltage across
one of the resistors divided by that resistorʹs value.

Question 5

Three 2 V cells in series with one in series-opposing would yield 2 V.

Question 6

If a resistor is rated at 1/2 W, it can safely dissipate 0.325 W.

Question 7

If a resistor is dissipating 1/4 W, it can supply 1/4 W to the load.

Question 8

According to Kirchhoffʹs Voltage Law, the sum of the individual voltage drops in a series circuit
equals the source voltage.

Question 9

A series circuit has multiple current paths.

Question 10

If and resistors are wired in series, the total resistance is

Question 11

Kirchhoffʹs Voltage Law states that the algebraic sum of all the voltages around a closed path is zero.

Question 12

Calculate the current in Figure

A)3.2 mA
B)0 A
C)12 mA
D)1.6 mA

Question 13

Calculate in Figure

A)0.0256 mW
B)0.256 mW
C)25.6 mW
D)2.56 mW

Question 14

Calculate in Figure .

A)
B)
C)
D)

Question 15

Voltage sources in series increase both voltage and current capacity.

Question 16

Total power dissipated in a series circuit equals source voltage multiplied by current.

Question 17

In a series circuit, the current is the same at every point in the circuit.

Question 18

If and resistors are wired in series, the total resistance is

Question 19

What is the total resistance in Figure 4-1 if and

A)
B)
C)
D)

Question 20

n Figure 4-1. opens, then RT is ________.

A)
B)
C)
D)

Question 21

If R2 shorts in Figure 4-1, the total circuit power ________.

A)increases
B)remains the same
C)decreases
D)depends upon the source voltage

Question 22

Calculate PT in Figure and all three resistors are each

A)23.6 mW
B)70.9 mW
C)22 W
D)709 mW

Question 23

Two resistors are wired in series across a 20 V source. How much voltage does each resistor drop?

A)
B)100 mA
C)20 V
D)10 V

Question 24

If resistor are connected in series, total resistance equals ________.

A)
B)the average of the three values
C)
D)

Question 25

A otentiometer is connected across a 5 V source. If the voltage from the wiper to the lower end of the potentiometer is 1.2 V, what is the resistance of that lower part?

A)
B)
C)
D)

Question 26

opens in Figure 4-1, the total power dissipated ________.

A)increases to maximum
B)will depend upon the source voltage
C)decreases to zero
D)remains the same

Question 27

Four resistors are connected in series across an 18 V source. Three resistors drop 0 V and one resistor drops 18 V. Whatʹs the trouble?

A)The three resistors are open.
B)One resistor is open.
C)Two of the resistors are shorted.
D)There is no trouble; these voltages are normal.

Question 28

If 12 V and -19 V sources are connected so their total voltage is -7 V, they are ________.

A)series opposing
B)series aiding
C)connected dangerously
D)in parallel

Question 29

What is the total supply voltage if 16 V and 12 V sources are wired in series opposing?

A)12 V
B)4 V
C)28 V
D)16 V

Question 30

A and resistor are connected across a 68 V source. How is the voltage divided?

A)34 V and 34 V
B)22 V and 12 V
C)44 V and 24 V
D)68 V and 68 V

Question 31

Calculate in Figure

A)22.4 V
B)27.6 V
C)47.3 V
D)30.3 V

Question 32

-1.2 V, +5 V and +6 V batteries are connected in series. The total voltage is ________.

A)9.8 V
B)1.3 V
C)12.2 V
D)1.2 V

Question 33

How much voltage is dropped across R2 and R3 in Figure

A)
B)
C)
D)

Question 34

If and they are wired in series across a 20 V source, what is VR1 and ?

A)
B)
C)
D)

Question 35

Calculate VT in Figure

A)14.7 V
B)4.7 V
C)10 V
D)30 V

Question 36

Calculate IT in Figure

A)1 mA
B)6 mA
C)4.26 mA
D)2.13 mA

Question 37

If 12 V and 17 V sources are wired in series aiding, what is the total supply voltage?

A)29 V
B)17 V
C)5 V
D)12 V

Question 38

shorts?

A)
B)
C)
D)

Question 39

When 50 V is applied to four series resistors, flows. what is the value of

A)
B)
C)
D)

Question 40

Based upon electron current flow, the polarity on the side of the resistor where current enters is ________. The polarity on the side of the resistor where current exits is ________.

A)positive, positive
B)positive, negative
C)negative, positive
D)negative, negative

Question 41

If five equal resistors dissipate a total of 10 W in a series circuit, how much power does each resistor dissipate?

A)50 W
B)10 W
C)2 W
D)5 W

Question 42

Four series resistors are connected across a 30 V source and carry what is the value of ?

A)
B)
C)
D)

Question 43

An open in a series circuit results in:

A)no current flow.
B)source voltage appearing across the open.
C)no power dissipation.
D)all of these.

Question 44

The voltage drop across any resistor or combination of resistors in a series circuit equals:

A)the ratio of the resistance values to the total resistance times the source voltage.
B)the product of the circuit current times the resistance value.
C)the applied voltage across the resistor (A).
D)all of these.

Question 45

If a resistor are in series, which resistor drops the most voltage?

A)
B)
C)
D)That canʹt be determined from the given information.

Question 46

Three resistors are connected in series across a 60 V source. If then what is the voltage drop across ?

A)14.3 V
B)45.7 V
C)19 V
D)26.7 V

Question 47

Refer to Figure 4-2a. Voltage B to ground is less than normal. What could be the cause of failure?

A)short between A and B
B)open between B and C
C)open between C and D
D)short between E and D

Question 48

Circuit ground or chassis ground can be thought of as a:

A)neutral connection point.
B)common point.
C)reference point.
D)all of these

Question 49

A potentiometer is connected across a 15 V source. If the voltage from the wiper to the lower end of the potentiometer is 3.2 V, what is the resistance of that lower part?

A)
B)
C)
D)

Question 50

Two resistors are in series across a 12 V source. If each resistor equals what is the voltage across each resistor?

A)9 V
B)12 V
C)3 V
D)6 V

Question 51

If a resistor are connected in series across a 9 V battery, the current equals ________.

A)36.3 mA
B)327 mA
C)22.3 mA
D)27.6 A

Question 52

If a and resistor are connected in series across a 12 V source, the voltage across the 10 k resistor is ________ and the voltage across the resistor is ________.

A)4 V, 8 V
B)4 V, 4 V
C)8 V, 4 V
D)8 V, 8 V

Question 53

In a series circuit, total power is calculated as:

A)
B)
C)
D)

Question 54

Refer to Figure 4-2a. Voltage from C to ground is 100 V. What is the probable cause of failure?

A)open between E and D
B)short between A and B
C)open between A and B
D)voltage reading is normal

Question 55

A short in a series circuit results in:

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

Question 56

If -12 V and -6 V are connected so they equal -18 V, these sources are ________.

A)connected dangerously
B)in parallel
C)series opposing
D)series aiding

Question 57

One of the most popular applications of a potentiometer is as an adjustable voltage divider also known as a:

A)divider control.
B)volume control.
C)current control.
D)voltage control.

Question 58

If 5 V and 16 V power supplies are connected in series aiding, what is the total voltage?

A)21 V
B)24 V
C)80 V
D)16 V

Question 59

If each of the six resistors in a series circuit drops 5 V, the source voltage ________.

A)depends on the current
B)equals 30 V
C)equals 5 V
D)depends on the resistor values

Question 60

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

A)the largest resistor.
B)the smallest resistor.
C)the first resistor.
D)any resistor, since the current is the same throughout the circuit.

Question 61

What is the easiest, most practical measurement performed during troubleshooting?

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

Question 62

What type of resistor could be used as variable voltage-divider?

A)rheostat
B)potentiometer
C)thermistor
D)any one of the above

Question 63

Refer to Figure 4-2a. The resistor between points E and D looks charred. What most likely would cause this?

A)short between A and D
B)open A and the power supply
C)short between A and B
D)Any of these could cause this problem.