Description : Two 100 watt light bulbs are connected in parallel across a 100 volt power supply. The total power developed in the circuit is _______________. A. 200 watts B. 100 watts C. 50 watts D. equal to the product of the amperes times the voltage in each branch
Last Answer : Answer: A
Description : An LED is operated on a 12 volt automobile circuit. The voltage drop across the LED is 2 volts and the current must be limited to 50 milliamps to prevent its overheating and destruction. What size resistor must be used? w) 60 ohms x) 100 ohms y) 120 ohms z) 200 ohms
Last Answer : ANSWER: Z -- 200 OHMS
Description : If there is a reduction in the normally supplied frequency to a 120/240 volt, threephase AC current motor from 60 hertz to 55 hertz, the motor would _____________. A. run at a slower speed B. operate at a lower current C. overheat D. trip off the line
Description : The distance between a generator and its load is 100 feet. What would be the approximate total voltage drop across a two wire supply cable if the current were 5.5 amperes and the resistance of the wire were 2.525 ohms per 1,000 feet? A. 0.5 volts B. 1.38 volts C. 1.90 volts D. 2.77 volts
Last Answer : Answer: D
Description : What current is required to light two 75 watt lamps and one 40 watt lamp when connected in series to a 120 volt power source? A. 0.161 amperes B. 0.631 amperes C. 1.583 amperes D. 6.199 amperes
Last Answer : Answer: C
Description : What is the total resistance of the electrical circuit illustrated if the resistance of R1 is 2 ohms, R2 is 4 ohms, and R3 is 4 ohms with a 6 volt battery? EL-0021 A. 0.01 ohms B. 0.10 ohms C. 1.00 ohms D. 10.00 ohms
Description : Electric current is the flow of electrons through a conductor. The rate of this flow is measured as ___________. A. volts/watt B. amperes/centimetre C. coulombs/second D. ohms/volt
Description : When troubleshooting most electronic circuits, 'loading effect' can be minimized by using a voltmeter with a/an ___________________. A. input impedance much greater than the impedance across which the voltage ... sensitivity of less than 1000 ohms/volt D. sensitivity of more than 1000 volts/ohm
Description : Which of the following statements is true if a 100 watt lamp and a 75 watt lamp are connected in parallel across a 100 volt power supply? A. The 75 watt lamp will draw as much current as the 100 ... Current flow will be the same across each lamp. D. The 75 watt lamp will have a higher resistance.
Description : What power is consumed by a heating element using a current of 20 amperes at 120 volts? A. 20 watts B. 66.67 watts C. 720 watts D. 2400 watts
Description : The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the _____________. A. prime mover speed B. exciter output voltage C. load on the alternator D. number of poles
Last Answer : Answer: B
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 : What is the maximum current allowed to be drawn from the secondary of a 2 KVA step-down transformer with a turns ratio of four to one if connected across a 440 volt line? A. 1.1 amps B. 4.5 amps C. 18.1 amps D. 22.7 amps
Description : A load with an impedance of 440 ohms is connected across the secondary of the transformer illustrated. If the input voltage is 110 VAC and the step-up ratio is 10 to 1, what will be the primary current? EL-0055 A. 2.5 amps B. 25 amps C. 250 amps D. current cannot be determined with information given
Description : A load with an impedance of 440 ohms is connected across the secondary of the device illustrated. If the input voltage is 110 VAC and the step-up ratio is 10 to 1, what will be the primary current? EL-0055 A. 2.5 amps B. 25 amps C. 250 amps D. current cannot be determined with information given
Description : Four amperes of current are measured through a 24 ohms resistor connected across a voltage source. How much voltage does the source produce? A.960 V B.9.6 V C.96 V D.8 V
Last Answer : Four amperes of current are measured through a 24 ohms resistor connected across a voltage source. How much voltage does the source produce? A.960 V B.9.6 V C.96 V D.8 V
Description : What is the impedance of a one microfarad capacitor at 60 Hertz: w) 16,700 ohms x) 2,650 ohms y) 3.8x10-4 ohms z) 6x10-5 ohms
Last Answer : ANSWER: X -- 2,650 OHMS
Description : What will be the frequency of a three-phase, six pole, AC generator operating at 1800 revolutions per minute? A. 60 hertz B. 90 hertz C. 120 hertz D. 180 hertz
Description : When the circuit shown in the illustration is operating correctly, the voltage at the reference electrode will be kept in the optimum range of ____________. EL-0090 A. 0.01 - 0.05 volt B. 0.80 - 0.85 volt C. 35 - 60 volts D. 100 - 115 volts
Description : A final amplifier of a radio transmitter draws 250 mA of plate current when the plate supply voltage is 1400 volts. If the plate circuit efficiency is 80% and the transmitter is connected to an antenna having a feed impedance of 70 ohms, ... at the feed-point? A. 4.0 A B. 2.2 A C. 1.25 A D. 2.0 A
Last Answer : D. 2.0 A
Description : Which of the listed sections of an emergency switchboard is used to supply power for alarm signals under emergency conditions? A. The generator and bus transfer section B. The 450 volt, 60 cycle, 3 phase bus C. The 120 volt, 3 phase, 60 cycle bus D. The 24 volt DC bus
Description : The electrical schematic shown in the illustration indicates the lighting feeder circuit is _____________. EL-0014 A. three phase, 450 volt, and 60 cycle B. three phase, 120 volt, and 60 cycle C. single phase, 120 volt, and 60 cycle D. not specified
Description : For a given base voltage and base volt-amperes, the per unit impedance value is x. For the doubled base values of both voltage and volt-amperes, the per unit impedance will be (a) 2x (b) 0.25x (c) 0.5x (d) no change
Last Answer : Answer is 2x Base impedance =(base voltage) ²/base current
Description : Two 220 volt lamps, one of 60 watt and the other of 75 watt are connected in series across a 440 volt supply. The potential difference across 60 watt lamp will be: A) 195 volt B) 220 volt C) 245 volt D) 440 volt
Last Answer : Two 220 volt lamps, one of 60 watt and the other of 75 watt are connected in series across a 440 volt supply. The potential difference across 60 watt lamp will be: 245 volt
Description : Figure 'D' of the diagram shown in the illustration has a turns ratio of four to one. If a three-phase 440 volt supply is connected to terminals 'A-B-C', what voltage should develop across terminals 'a-b-c'? EL-0084 A. 64 volts B. 110 volts C. 190 volts D. 762 volts
Description : Figure 'C' of the diagram shown in the illustration has a turns ratio of four to one. If a three-phase 440 volt supply is connected to terminals 'A-B-C', what voltage should develop across terminals 'a-b-c'? EL-0084 A. 64 volts B. 110 volts C. 190 volts D. 762 volts
Description : Figure 'B' of the diagram shown in the illustration has a turns ratio of four to one. If a three-phase 440 volt supply is connected to terminals 'A-B-C', what voltage should develop across terminals 'a-b-c'? EL-0084 A. 64 volts B. 110 volts C. 190 volts D. 762 volts
Description : Figure 'A' of the diagram shown in the illustration has a turns ratio of four to one. If a three-phase 440 volt supply is connected to terminals 'A-B-C', what voltage should develop across terminals 'a-b-c'? EL-0084 A. 64 volts B. 110 volts C. 190 volts D. 762 volts
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 battery is connected to a circuit containing three resistors in parallel. The values of the three resistors are 2 ohms, 3 ohms, and 6 ohms. What is the voltage of the battery if the total circuit current is 12 amps? A. 2 volts B. 6 volts C. 12 volts D. 24 volt
Description : The power supplied to a motor is six kilowatts at 120 volts. What is the impedance of the motor? A. 0.05 Ohms B. 0.50 Ohms C. 2.40 Ohms D. 24.00 Ohms
Description : As shown in the illustration, the circuit has been on the line for several days when component 'E1' burns out. The operator receives an alarm, switches over 'B' to energize the standby ... than required for the circuit therefore limiting the current through the alarm relay which will not pick up
Description : The ratio of the effective value of the counter EMF in volts, to the effective value of the current in amperes is called _____________. A. impedance factor B. capacitive reactance C. inductive reactance D. root mean square
Description : How many volts are necessary to provide a current of 10 amperes to a motor with an in-line resistance of 11 ohms? A. 21 volts B. 110 volts C. 220 volts D. 240 volts
Description : Electric current is the flow of electrons through a conductor; the rate of this flow is measured in ___________. A. volts B. amperes C. coulombs D. ohms
Description : Which of the following precautions should be taken when troubleshooting various power circuits using a common solenoid-type mechanical voltage tester (wiggins)? A. Never use this tester on circuits greater ... voltage expected in the circuit in order to prevent damage from an off-scale reading.
Description : The hook-on AC volt-ammeter consists essentially of a split-core and a rectifiertype instrument connected to the secondary winding of a _____________. A. potential transformer B. control transformer C. current transformer D. reactance transformer
Description : Three lamps are connected in parallel across a 120 Volt source. If one lamp burns out, the remaining two will be: A. Glow dimmer B. Glow brighter C. Not light D. Glow with the same brightness as before
Last Answer : Glow with the same brightness as before
Description : What is the maximum allowable primary current of a 2 KVA step-down transformer with a four to one turns ratio if connected across a 440 volt line? A. 1.1 amps B. 4.5 amps C. 18.1 amps D. 27.7 amps
Description : A 1000 watts heater is connected to a 240 V AC Supply. Then the current drawn by the heater is
Last Answer : A 1000 watts heater is connected to a 240 V AC Supply. Then the current drawn by the heater is 4.166 amperes
Description : Which of the electrical properties listed will always be the same for each component in a parallel circuit? A. Impedance B. Current C. Resistance D. Voltage
Description : In the illustrated circuit, what is the resistance across R2 if the battery voltage is 32 VDC, the resistance of R1 is 1.2 kohms and the current through R2 is 18.82 milliamps? EL-0036 A. 500 ohms B. 1,200 ohms C. 10 ohms D. The answer can not be found with the information given.
Description : For an overhead line, the surge impedance is taken as (a) 20-30 ohms (b) 70—80 ohms (c) 100—200 ohms (d) 500—1000 ohms (e) none of the above
Last Answer : (c) 100—200 ohms
Description : What is the wattage of a heating element drawing a current of 30 amperes, at 120 volts? A. 30 watts B. 99.97 watts C. 360 watts D. 3600 watts
Description : As shown in the illustration, the function of the switch labeled 'PFSW' is to determine the ______________. EL-0003 A. bus frequency B. reactive volt amperes of the bus C. frequency of either generator D. power factor of either generator
Description : Battery capacities are given in _____________. A. volts B. volt-amperes C. volt-hours D. ampere-hours
Description : What is the current through R2 of the circuit illustrated if the resistances of R1 is 2 ohms, R2 is 4 ohms, and R3 is 4 ohms with a 6 volt battery? EL-0021 A. 0.5 amp B. 1.5 amps C. 3.0 amps D. 6 amps
Description : What is the total current in the illustrated circuit with a 6 volt battery if the resistance of R1 is 2 ohms, R2 is 4 ohms, and R3 is 4 ohms? EL-0021 A. 0.6 amp B. 1 amp C. 4 amps D. 6 amps
Description : A 20 ohm resistor and a 60 ohm resistor are connected in parallel to a voltage source. If the current in the 60 ohm resistor is one ampere, the current in the 20 ohm resistor will be: w) 1/3 ampere x) 2/3 ampere y) 1 ampere z) 3 amperes
Last Answer : ANSWER: Z -- 3 AMPERES
Description : The inductance of a coil is measured in _____________. A. ohms B. volts C. henries D. amperes