Electrical THQ #5
A conductor with a cross-sectional area of one circular mil would have a diameter of __________. 0.001 inches 0.01 inches 0.1 inches 0.0001 inches
0.001 inches
Which of the AWG wire sizes listed below would have the smallest diameter? 14 0 0000 12
14
A wire is being used as a replacement having twice the length and one-half the cross-sectional area of the original wire. The resistance of this new wire, when compared to that of the original wire, is __________. The same as the original resistance Twice as much Four times as great One-half of the original resistance
Four times as great
Most conducting materials such as copper, aluminum, iron, nickel, and tungsten __________. Decrease in resistance with increased temperature Increase in resistance with decreased temperature Increase in resistance with increased temperature Increase in conductance with increased temperature
Increase in resistance with increased temperature
Which of the following materials is a good electrical insulator? Copper Silver Wood Gold
wood
Which of the following statements concerning copper wire sized by AWG numbers is correct? Number 10 AWG wire has a higher dielectric strength than 12 AWG wire. Number 12 AWG wire At 25°C has more resistance per 1000 ft than 10 AWG wire at 25°C. Number 12 AWG wire has a higher current rating than 10 AWG wire. Number 12 AWG wire is larger than number 10 AWG wire.
At 25°C has more resistance per 1000 ft than 10 AWG wire at 25°C.
The standard measuring unit of wire by its cross-sectional area, as used in American wire tables is the __________. Square millimeter Circular mils Cubic mils Cubic inch
Circular mils
Which of the listed classes of electrical insulation is suited for the highest operating temperature? Class 130 (B) Class 105 (A) Class 90 (O) Class 180 (H)
Class 180 (H)
Which of the following statements best describes the material known as varnished cambric? Rubber insulation coated with a layer of tin. Cotton cloth coated with insulating varnish. Felted asbestos sealed with varnish. Paper impregnated with mineral oil, specially wrapped with nonmetallic tape, and coated with varnish.
Cotton cloth coated with insulating varnish.
The resistance of electric wire will decrease as its __________. Directly as its length and directly as its cross-sectional area Inversely as its length and directly as its cross-sectional area Directly as its length and inversely as its cross-sectional area Inversely as its length and inversely as its cross-sectional area
Directly as its length and inversely as its cross-sectional area
The reason some electric cables are formed of stranded wire is to __________. Decrease the weight for a given size wire Increase their flexibility Increase the current carrying capability for a given size wire Assure good conductivity at junction points
Increase their flexibility
The resistance of a conductor varies __________. Directly as its length and directly as its cross-sectional area Inversely as its length and directly as its cross-sectional area Directly as its length and inversely as its cross-sectional area Inversely as its length and inversely as its cross-sectional area
Inversely as its length and directly as its cross-sectional area
Which of the following statements about copper wire sized by the AWG rating is correct? Number 12 AWG wire is larger than Number 10 AWG wire. Number 10 AWG wire has a higher dielectric strength than number 12 AWG wire. Number 12 AWG wire has a higher current rating than number 10 AWG wire. Number 12 AWG wire at 25°C has more resistance per 1000 feet than No. 10 AWG wire at 25°C.
Number 12 AWG wire at 25°C has more resistance per 1000 feet than No. 10 AWG wire at 25°C.
A common type of protective covering used on electrical conductors is __________. Silver sheathing Rubber or plastic Plain paper Babbitt sheathing
Rubber or plastic
The proper way to apply plastic electrical tape to an electric cable splice is to __________. Apply the tape in one non-overlapping layer only. Wind the tape so that each turn overlaps the turn before it. Apply tape to the braided cover, but avoid touching it. Heat the tape with a soldering iron for good bonding.
Wind the tape so that each turn overlaps the turn before it.
Electrical wire in general, when used aboard vessels must meet minimum requirements. Which of the following statements is/are correct? The only wire that does not have to be in a suitable enclosure or cover is the ground wire used with portable tools and lights. Wire must be copper stranded. Each wire must be 14 AWG or larger, regardless of locations and use. All of the above.
Wire must be copper stranded.
Which of the following characteristics is most critical in determining the size of the cable to be used in a particular circuit? Current rating Weight per unit length Voltage rating Inductance per unit length
current rating
The heating of conductors as a result of resistance in a distribution circuit causes a power loss expressed as __________. IR drop Line loss Line droop Hysteresis
line loss
The existing resistance of a conductor is dependent upon its length, cross-sectional area, __________. Capacitive reactance and material Material and insulation Inductive reactance and insulation Material and temperature
material and temperature
When the current flow through a copper wire increases, its __________. Temperature will increase Insulation will burn Resistance will decrease Conductivity will increase
temperature will increase
