Quiz 3

Question 1

In the United States, conductors are sized according to the ? standard or by the actual number of circular mil (CM) for the wire.

a. American Wire Gauge (AWG)
b. American National Standards Institute (ANSI)
c. National Wire Gauge (NWG)
d. National Electrical Code (NEC)

Answer 1

a. American Wire Gauge (AWG)

Question 2

The cross-sectional area of American conductors is expressed in units called ?.

a. circular mils
b. mil-foot
c. millimeters
d. square inches

Answer 2

a. circular mils

Question 3

Explain how to calculate the approximate cross-sectional area of a conductor in circular mils.

a. Measure the diameter of the conductor in centimeters. Multiply the result by 10,000; then find the square root.

b. Measure the diameter of the conductor in inches. Multiply the result by 1,000; then square it.

c. Measure the diameter of the conductor in inches. Multiply the result by 10,000; then find the square
root.

d. Measure the diameter of the conductor in millimeters. Multiply the results by 1,000; then square it.

Answer 3

b. Measure the diameter of the conductor in inches. Multiply the result by 1,000; then square it.

Question 4

Find the cross-sectional area of a conductor in millimeters squared when the diameter of the
conductor is 25 millimeters. Pi must be calculated as 3.14159. (Round the FINAL answer to two decimal places.)

Answer 4

490.87 mm ^2

Question 5

What is the formula for calculating the resistance of wire?

a. K×L
A= ━
R
b. K×A
R= ━
L
c. A
R= ━
K×L
d. K×L
R= ━
A

Answer 5

d. K×L
R= ━
A

Question 6

Calculate the resistance of a piece of aluminum wire with a diameter of 100 mils and a length of two miles, at 68°F. Hint: Be sure to first convert mils to cmils and use the K value for aluminum found in the reference. (Round the FINAL answer to two decimal places.

Answer 6

18.69 ohms

Question 7

What is the approximate gauge of a wire that has a diameter of about 100 mils?

a. #6 (AWG)
b. #8 (AWG)
c. #10 (AWG)
d. #12 (AWG)

Answer 7

c. #10 (AWG)

Question 8

You wish to use #18 tungsten wire at 20°C to make a 10 Ω resistor. What length of wire will be required for this job? Hint: Be sure to use the K value found in the reference. (Round the FINAL answer to two decimal places.)

Answer 8

479.29 ft.

Question 9

The resistance of a conductor is directly proportional to its length and ? and inversely proportional to its cross sectional area.

a. current carrying capacity
b. power rating
c. specific resistance
d. voltage rating

Answer 9

c. specific resistance

Question 10

Specific resistance is also called ? and is abbreviated with the capital letter K or the Greek letter ρ (rho).

a. inductance
b. Load value
c. Ohms
d. Resistivity

Answer 10

d. Resistivity

Question 11

If a 250-foot #12 copper conductor has a resistance of 0.397 Ω, how much is the resistance of the same conductor at 800 feet? (Round the FINAL answer to two decimal places.)

Answer 11

1.27 ohms

Question 12

What is the resistance of a 600-foot #12 (solid) aluminum conductor? Hint: The resistance of the conductor is 3.18 Ohms/1000 feet. (Round the FINAL answer to two decimal places.)

Answer 12

1.91 ohms

Question 13

What is the formula to find the cross-sectional area of a cable in square inches?

a. d = (A/2)² × π
b. A = d/2 × π
c. A = (d/2)² + π
d. A = (d/2)² × π

Answer 13

d. A = (d/2)² × π

Question 14

What is the formula to find the voltage drop of the conductors to and from the load?

a. VD = 2 × [CM / (K × L)] × I
b. VD = [(K × L) / 2 × CM] × I
c. CM = 2 × [(K × L) / VD × I]
d. VD = 2 × [(K × L) / CM] × I

Answer 14

d. VD = 2 × [(K × L) / CM] × I

Question 15

What is the formula used to find line loss?

a. P = I² × R
b. R = I² × P
c. P = I² / R
d. I = P² × R

Answer 15

a. P = I² × R

Question 16

Lamps have both a ? rating and a ? rating.

a. current / resistance
b. resistance / voltage
c. voltage / current
d. voltage / power

Answer 16

d. voltage / power

Question 17

Different wattage ratings are achieved for lamps with the same voltage rating by changing the value of the ?.

a. capacitance
b. current
c. inductance
d. resistance

Answer 17

d. resistance

Question 18

The higher the resistance, the lower the rated wattage of a lamp.

True or False?

Answer 18

True.

Question 19

Why will a lamp with a 100-ohm filament burn brighter than a lamp with a 300-ohm filament?

a. There is less resistance in the 100-ohm filament. Therefore, less current will flow, causing more heating and incandescent action.

b. There is less resistance in the 100-ohm filament. Therefore, more voltage will be applied to the circuit.

c. There is less resistance in the 100-ohm filament. Therefore, more current will flow, causing more heating and incandescent action.

d. There is more resistance in the 100-ohm filament. Therefore, more current will flow, causing more heating and incandescent action.

Answer 19

c. There is less resistance in the 100-ohm filament. Therefore, more current will flow, causing more heating and incandescent action.

Question 20

Which of the following is not a characteristic that determines the resistance of a conductor?

a. cross-sectional area
b. Length of conductor
c. Temperature of conductor
d. Type of material
e. Voltage rating of the conductor

Answer 20

e. Voltage rating of the conductor

Question 21

The unwanted heat generated by an incandescent lamp is considered a power loss.

True or False?

Answer 21

True.

Question 22

Electrical energy usage is measured in volt-amperes.

True or False?

Answer 22

False

Question 23

Each kilowatt hour equals ?.

a. 100 watt hours
b. 500 watt hours
c. 1,000 watt hours
d. 10,000 watt hours

Answer 23

c. 1,000 watt hours

Question 24

The unit of measurement used by electric companies to determine a monthly electric bill is the ?.

a. kilowatt-minute
b. kilowatt-hour
c. kilowatt-day
d. kilowatt-month

Answer 24

b. kilowatt-hour

Question 25

The measurement kilowatt-hour expresses how much energy is used over a period of time. True or False?

Answer 25

True.