conductors and resistors
14.08 amps
a coil is wound with 200 feet of no 16 tinned copper wire and connected to a 12 volt battery. What is the current if the resistance per 1000 of no 16 tinned copper wire is 4.26 ohms
7.04amps
a coil is wound with 400 ft of no 16 tinned copper wire and connected to a 12 volt battery. What is the current if the resistance per 1000 ft of No. 16 tinned copper wire is 4.26 ohms?
four times as great
a wire is being used as a replacement having twice length and one half the ross sectional area of the original wire. What will be the resistance of this new wire, when compared to that of the original wire?
installed with watertight stuffing tubes
all electric cables passing through watertight bulkheads must be configured in what manner?
four times that of the original wire
compared to the original wire, what will be the resistance of a replacement wire having twice the length and one half the ross sectional are of the original?
wire must be of the stranded copper type
electrical wire in general, when used aboard vessels must meet minimum requirements which is _____
by the band markings on the resistor
how can the nominal resistance value of a typical carbon resistor in a circuit best be determined?
directly as its length and inversely as its cross-sectional area
how does the resistance of a conductor vary?
limiting internal hot spot temperature
how is electrical conductor insulation classed?
quartered
if the length of a wire is halved and the cross-sectional area is doubled, what will be the resistance of the wire as compared to the original wire?
continuity of the conductor
if you disconnect and arrange both ends of a conductor of a multi-conductor cable without any contact between the individual conductors, what would a low ohmic value between the ends of a single conductor indicate?
conductor resistance increases with increased temperature
most conducting materials such as copper, aluminum, iron, nickel, and tungsten behave in such as way as the resistance and conductance is predictably effected by temperature.
material and temperature
the existing resistance of al conductor is dependent upon its length, cross-sectional area, and what else?
increases in a predictable way
the resistance of most conducting materials will change as a result of temperature change. What will happen to eth resistance of copper wire when the temperature increases?
circular mills
the standard measuring unit of wire by its cross-sectional area, as used in American wire tables is measured how?
at right angles and as far as practicable from each other
to minimize magnetic field interaction between electrical conductors in physical proximity, what is the best practice?
20
what AWG wire sizes listed below would have the smallest diameter?
number 12 AWG wire at 25 C has more resistance per 1000ft than no 10 AWG wire at 25C
what concerning copper wire sized by AWG numbers is correct?
resistor wattage rating one half that required for the circuit
what condition would most likely lead to the failure of a resistor due to overheating?
rubber or plastic
what is a common type of protective covering used on electrical conductors
stranded wire increases their flexibility over solid wire and reduces skin effect losses
what is the reason that some electric cables are formed of stranded wire?
number of zeros following the first two significant figures in the resistance value
what is the third color band used to indicate?
cross sectional area increases
what will cause the resistance of electric wire to decrease?
its reliability factor will decrease
what will happen to a carbon resistor operating in electrical equipment that is not properly cooled?
temperature will increase
what will happen to a copper wire when the current flow through the wire increases in value?
.001 inches
what would be the diameter of a conductor with a cross-sectional area of one circular mil
a watertight stuffing tube capable of accepting packing should be employed
when electrical cables penetrate watertight bulkheads, what must be provided for?
remains the same
when the length and cross sectional area of a replacement wire are both tripled, what will be the value of the resistance as compared to the original wire
current rating
which of the following characteristics is most critical in determining the wire gauge size of the cable to be used in a particular circuit
18
which solid AWG wire size has the smallest physical cross-sectional area?
obtain the flexibility required for easy handling and reduces skin effect losses
why are large cable sizes often formed as individual conductors comprised of several smaller strands?
is able to pass current with little opposition
why is copper often used as an electrical conductor
circular mills
with what units of measure is the cross-sectional area of shipboard electrical cable expressed
a conductor with green insulation would be used
you are supervising a new electrician concerning an onboard test of an electrical component using a test rig with flexible cable. What color coded insulated conductors can only serve as an equipment safety ground and shall not be used as a current carrying conductor