Description : The resistance of most conducting materials will change as a result of temperature change. The resistance of copper will _____________. A. increase as temperature decreases B. decrease as temperature decreases C. remain the same between 20°F and 110°F D. remain the same between 68°F and 230°F
Last Answer : Answer: B
Description : Most conducting materials such as copper, aluminum, iron, nickel, and tungsten _____________. A. increase in resistance with increased temperature B. increase in resistance with decreased ... C. decrease in resistance with increased temperature D. increase in conductance with increased temperature
Last Answer : Answer: A
Description : Electric cables are formed of stranded wire to ____________. A. increase the current carrying capability for a given size wire B. increase their flexibility C. decrease the weight for a given size wire D. assure good conductivity at junction points
Description : A megger is being used to test the insulation of an AC generator. The resistance value of a dry, clean winding will _____________. A. continue to rise as test potential is maintained, ... , becoming fairly steady after 5-7 minutes D. stabilize after approximately 2-4 minutes of fluctuation
Description : An increase in the amount of current flow through the armature of a shunt motor is the final result of a/an _____________. A. increase in the load on the motor B. decrease in the load on the motor C. increase in counter EMF D. decrease in armature torque
Description : When a megohmmeter is used to test the dielectric strength of wire insulation, the initial dip of the pointer toward 'zero' is caused by _____________. A. good insulation B. the leakage of ... of dirty insulation C. the capacitance of the circuit D. the dielectric absorption effect of the insulation
Last Answer : Answer: C
Description : The resistance of electric wire will decrease as its _______________. A. length increases B. cross-sectional area increases C. temperature increases D. percent of metallic purities increases
Description : You are testing the insulation in an AC generator with a megohmeter. The resistance value of a dry, clean winding will ____________. A. continue to rise as the test potential is maintained, ... fairly steady after 5 to 7 minutes D. stabilize after approximately 2 to 4 minutes of fluctuation
Description : When shipboard electrical distribution circuits are connected in parallel, additional parallel circuits will cause the total circuit resistance to _____________. A. increase, causing a drop in the line current B ... an increase in the line voltage D. decrease, causing an increase in the line current
Last Answer : Answer: D
Description : When the voltage remains constant, and the resistance increases in a series circuit, current flow _____________. A. decreases B. remains the same C. increases D. increases by the square
Description : When the voltage remains constant and the resistance is increased in a series circuit, the flow of current _____________. A. increases by the square of the original value B. increases C. remains the same D. decreases
Description : The existing resistance of a conductor is dependent upon its length, cross-sectional area, _____________. A. temperature and insulation B. material and insulation C. resistive coefficient and material D. material and temperature
Description : When a megohmmeter is being used on a alternating current machine, the meter pointer will dip toward 'zero' and then gradually rise to the true resistance value if the motor insulation is _____________. A. grounded B. good C. shorted D. dirty
Description : When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter pointer _____________. A. fluctuating around a ... slightly downscale as voltage is applied D. continually rising as the test voltage is applied
Description : When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter's pointer _____________. A. dipping toward ... kicking slightly down scale as voltage is applied D. fluctuating around a constant resistance reading
Description : When a megohmmeter is used to test insulation, the gradual rise of the pointer reading as a result of continued cranking, is caused by _____________. A. good conductor resistance B. the ... insulation C. the inductive reactance of the windings D. the dielectric-absorption effect of the insulation
Description : In preparing to take insulation resistance readings on a main generator, the windings should be grounded for about 15 minutes prior to the test to _____________. A. allow accurate zeroing of the meter ... the windings D. help the windings to cool to the same temperature as the ground test connection
Description : When the length and cross sectional area of a wire are both tripled, the resistance _____________. A. increases nine fold B. increases three fold C. remains the same D. decreases six fold
Description : A circuit breaker and a fuse have a basic similarity in that they both _____________. A. can be reset to energize the circuit B. should open the circuit when overloaded C. will burn out when an over current flow develops D. all of the above
Description : With increase in temperature, the thermal conductivity of fresh lubricating oil (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depends on its composition
Last Answer : (B) Decreases
Description : Copper is often used as an electrical conductor because it _______________. A. has high resistance at low temperatures B. has a highly polished surface C. is able to pass current with little opposition D. holds insulation together well
Description : With increase in temperature, the thermal conductivity of a gas (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease depending on the type of gas
Last Answer : (A) Increases
Description : Thermal conductivity of a gas at low density, __________ with increase in temperature. (A) Decreases (B) Increases (C) Remains unchanged (D) May increase or decrease; depends on the gas
Last Answer : (B) Increases
Description : Which of the listed conditions describes the effect on intrinsic semiconductor operation as a result of a temperature increase? A. Additional heat sinks will be required B. Conductivity will increase C. Conductivity will decrease D. Resistivity will increase
Description : Electrical insulation is classed by the _____________. A. International Association of Electrical Manufacturers B. approximate operating voltage and current expected C. U.S. Coast Guard D. temperature stability of the manufacturing material(s)
Description : The basic meter movement responds to the flow of current through its coil. Therefore, this meter movement may be used as a/an _____________. A. voltmeter by placing a resistance in parallel with the ... in parallel with the coil D. ammeter by placing a low resistance in parallel with the coil
Description : A capacitor is to be tested with a megohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should _____________. A. immediately swing to the maximum resistance value ... and gradually decrease D. swing to zero then gradually increase with slight pointer movements down scale
Description : With the increase of temperature, the Col-burn jH factor (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depending on temperature
Description : The true power indicated by a wattmeter depends on the current flow through the load, the magnitude of the potential across the load, and the _____________. A. power factor of the load B. angle of coil displacement C. inertia of the movable coil D. high resistance from the load
Description : To limit the current flow through a DC voltmeter to as low a value as possible, the moving coil circuit is provided with a/an _____________. A. high series resistance B. high parallel resistance C. series inductor D. external shunt
Description : If many turns of an alternating current coil for a contactor become short circuited, the coil _____________. A. will continue to operate B. will probably burn out immediately C. will operate on reduced current D. temperature will drop
Description : If many turns of an alternating current coil for a contactor become short circuited, the coil _____________. A. temperature will drop B. will probably burn out immediately C. will continue to operate D. will operate on reduced current
Description : Before using a volt-ohmmeter to measure resistance readings, you should _____________. A. replace all batteries B. test the insulation resistance of the leads C. make sure the test leads do not touch D. hold the leads together and 'zero' the meter
Description : When using a megohmmeter to test insulation, good insulation will be indicated by _____________. A. slight kicks of the needle down scale B. a downward dip followed by a gradual climb to the true resistance ... C. a gradual rise in the pointer reading at the outset D. the initial dip of the pointer
Description : On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test _____________. A. insulation resistance B. eddy currents C. capacitance D. armature reactance
Description : The insulation resistance of electric equipment and machinery should be tested for the lowest normal insulation values _____________. A. immediately after shutting down the machine B. every time the brush rigging is ... starting up the machine D. every 30 days whether the machine is in use or not
Description : The arrow drawn through the resistor shown in the illustration indicates that it is _____________. EL-0086 A. for use in low power applications B. a carbon composition type C. a wire-wound type D. one whose resistance is variable
Description : A coil is wound with 400 feet of No. 16 tinned copper wire and connected to a 12 volt battery. What is the current if the resistance per 1000 feet of No. 16 tinned copper wire is 4.26 ohms? A. 4.8 amps B. 7.06 amps C. 10.65 amps D. 11.27 amps
Description : 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 feet of No. 16 tinned copper wire is 4.26 ohms? A. 1.14 amps B. 7.04 amps C. 10.22 amps D. 14.08 amps
Description : Which of the following statements about copper wire sized by the AWG rating is correct? A. Number 12 AWG wire has a higher current rating than number 10 AWG wire. B. Number 10 AWG wire has a higher ... Number 12 AWG wire at 25°C has more resistance per 1000 feet than No. 10 AWG wire at 25°C.
Description : Which of the following statements concerning copper wire sized by AWG numbers is correct? A. Number 12 AWG wire has a higher current rating than 10 AWG wire. B. Number 12 AWG wire at 25°C has more ... dielectric strength than 12 AWG wire. D. Number 12 AWG wire is larger than number 10 AWG wire.
Description : With increase in porosity, the thermal conductivity of a solid substance (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depends on the solid
Description : When changing fuses and the spring clips are found to have lost their grip, they should be replaced or _____________. A. tightened firmly with insulated pliers B. clip clamps should be used C. wired closed with uninsulated, varnished copper wire D. carefully bent back to their original shapes
Description : Decreasing the frequency in a capacitive circuit while maintaining a constant circuit voltage, will result in a/an _____________. A. increase in apparent power B. decrease in circuit current C. decrease in capacitive reactance D. decrease in total impedance
Description : If an induction motor were to be operated at 90% rated voltage, _____________. A. there would be an increase in starting torque B. starting current would increase slightly C. synchronous speed would decrease slightly D. the slip would increase
Description : When the current in a power transmission line is increased, the power loss _____________. A. increases as the square of the current B. decreases as the square root of the current C. remains the same, as it is independent of current flow D. increases in direct proportion as the current
Description : Resistance of a wire on increasing its temperature will a. increase with rise in temperature b. decrease with rise in temperature c. will remain same d. depends upon altitude of experimentation
Last Answer : a. increase with rise in temperature
Description : The insulation of electric generators during short idle periods should be _____________. A. allowed to cool slowly to ambient temperatures B. flashed with direct current to remove any residual ... using strip or space heaters D. relieved of all capacitive charge by grounding the conductors
Description : Moisture accumulating in electric motors and generator windings having a cold insulation resistance greater than 50,000 ohms may be baked out with internal heat. This heat can be developed by ____________. ... an electric welder and feeding it into the armature while running the motor at full speed
Description : When using a megohmmeter to test the dielectric strength of wire insulation, a continuous series of slight downscale kicks by the pointer is result of ____________. A. good insulation B. the ... dirty insulation C. the capacitance of the windings D. the dielectric-absorption effect of the insulation