Description : Nickel-cadmium batteries are superior to lead-acid batteries at high discharge rates because they _______________. A. deliver a large amount of power and can be recharged in a shorter time B. need ... less mounting space C. have higher output voltages and require no maintenance D. all of the above
Last Answer : Answer: A
Description : Due to its construction, the component in figure 'A' shown in the illustration has which of the listed advantages compared to bipolar devices? EL-0078 A. Operates with higher voltages and ... as a controllable rectifier. D. Has very high input resistance and uses practically no gate current.
Last Answer : Answer: D
Description : At high discharge rates, nickel-cadmium storage batteries are superior to lead-acid batteries because they __________. A. require fewer cells for the same voltage and less mounting space B. are able to ... times without much damage D. have no individual cells to replace at the end of useful life
Last Answer : Answer: C
Description : Nickel-cadmium storage batteries are superior to lead-acid batteries because they __________. A. put out higher voltages and require no maintenance B. can remain idle and keep a full charge for a long time C. need fewer cells in series and use less mounting space D. all of the above
Last Answer : Answer: B
Description : Which of the following statements is true concerning simple parallel resistance circuits? A. The total current flow equals the sum of the individual currents. B. The total current flow equals the ... resistance. D. The total voltage equals the sum of the individual voltages across each resistance.
Description : Which of the following statements concerning a simple parallel resistance circuit is correct? A. The voltage drop across each resistor is the same. B. The total current flow equals the reciprocal ... resistances. D. The total voltage equals the sum of the individual voltages across each resistance.
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 : Ratio of voltages is inverse ratio of the A. transformer B. resistor C. iron core D. current
Last Answer : current
Description : The primary function of an electric motor is to ___________. A. develop torque B. generate high voltages C. produce a magnetic field D. generate high electrical resistance
Description : Violent gassing developed by a lead-acid battery during charging indicates that the ____________. A. plate separators are grounded B. cell voltages are excessive C. specific gravity in insufficient D. charging rate is excessive
Description : When charging lead-acid batteries, the charging rate should be reduced as the battery nears its full charge to ____________. A. prevent damaging battery plates B. allow equalization of cell voltages C. reduce lead sulfate deposits D. increase lead peroxide formation
Description : When charging lead-acid batteries, you should reduce the charging rate as the battery nears its full charge capacity to ______________. A. prevent excessive gassing and overheating B. allow equalization of cell voltages C. reduce lead sulfate deposits D. increase lead peroxide formation
Description : The state of charge of a lead acid storage battery is best indicated by the _____________. A. testing of the individual cell voltages B. ampere hour capacity of the battery C. specific gravity of the electrolyte D. total cell voltages
Description : Ungrounded neutral transmission system is not recommended because of system (a) insulation being overstressed due to over voltages (b) insulation overstress may lead to failure and subsequent phase to phase faults (c) being inadequately protected against ground fault (d) all of the above
Last Answer : (d) all of the above
Description : In a series-RLC circuit, what is the condition of the circuit if there is high impedance, low current, and low reactance voltages
Last Answer : Nonresonant (circuit is either above or below resonance)
Description : The electrical diagram shown in the illustration shows _____________. EL-0021 A. 'R1', 'R2', and 'R3' are connected is series B. 'R1', 'R2', and 'R3' are connected in parallel C. the voltages measured across ... if 'R1', 'R2' and 'R3' have different values D. the total resistance equals R1 + R2 + R3
Description : Which of the following statements is correct for the illustrated circuit? EL-0020 A. 'R1', 'R2', and 'R3' are connected in series. B. 'R1', 'R2', and 'R3' are connected in parallel. C. The voltages measured across 'R1', 'R2', and 'R3' are equal. D. The total resistance equals 1/R1 + 1/R2 + 1/R
Description : When a series voltage regulator is used to control output voltages, any increase in the input voltage results in an increase/a decrease (which one) in the resistance of the regulating device.
Last Answer : An increase.
Description : When a series voltage regulator is used to control output voltages, any increase in the input voltage results in an increase/a decrease in the resistance of the regulating device.
Last Answer : Increase.
Description : A ferrite core has less eddy current loss than an iron core because ferrites have (A) High resistance. (B) Low resistance. (C) Low permeability. (D) High hysteresis.
Last Answer : (A) High resistance.
Description : In inverting amplifier, the phase difference between input and output voltages must be A. 30° B. 45° C. 90° D. 180°
Last Answer : 180°
Description : Ratio of voltages is equal to ratio of A. iron sheets in core B. coil C. number of turns in coil D. all of above
Last Answer : number of turns in coil
Description : One important difference between wye-connected and delta-connected generators is that delta connections have ____________. A. line voltages equal to the vector sum of the phase voltages B. phase voltages 90° ... C. line current equal to the phase current D. line voltage equal to the phase voltage
Description : What precaution should be taken with a vessel's impressed current cathodic protection system after a drydocking period during which the hull has been painted? A. Output currents should be carefully monitored ... slight (10-15%) overcurrent to the anodes should be allowed in order to speed drying.
Description : If reading AC current with the illustrated device and unsure of the range as a precaution , the first step should be to _________. EL-0047 A. secure power and test for voltage B. disconnect the ... resistance and use Ohm's law to calculate current D. unable to safely measure current with the device
Description : When paralleling two alternators, the synchronizing lamps remain lit as the synchroscope pointer approaches the 0°. This indicates the _____________. A. incoming alternator is running too fast B. alternator ... apart C. synchroscope is defective or broken D. alternator power factors are in phase
Description : AC and DC generators are similar in that they _____________. A. both generate alternating voltages B. both rectify the voltage before delivery C. are constructed at the same physical size for the same kilowatt rating D. both supply three-phase power
Description : The potentiometers shown in the illustration are supplied with both (+) and (-) voltages as well as a reference to ground ________________. EL-0095 A. so there is always a spare power ... , the other for relay operation and the potentiometers are in positions where they can be accidentally touched
Description : Basic operating characteristics of the operational amplifier such as gain and stability are the function of its _____________. A. differential input stage B. power output stage C. feedback circuit D. supply voltages
Description : The purpose of a magnetic relay is to _____________. A. open a circuit only in the event of overload B. remotely open and close contacts C. provide overcurrent protection during starting D. relay voltages at increased power
Description : Electrostatic type instruments are mainly used for measurement of: a) Heavy currents b) Low currents c) Low voltages d) High voltages
Last Answer : Ans: D
Description : What are the most common insulators used for extremely high voltages?
Last Answer : Varnished cambric and oil-impregnated paper.
Description : Measurement of high dc-voltages is usually done by using
Last Answer : electrostatic
Description : Electrostatic voltmeters are particularly suitable for measuring high voltages because the construction is simplified due to
Last Answer : Electrostatic voltmeters are particularly suitable for measuring high voltages because the construction is simplified due to Large electrostatic forces.
Description : Why transmission voltages are high?
Last Answer : If current is high then I2R losses will be more .If I2R losses is more then heat generated is more. By heat or increasing temperature resistance will also be increase which will decrease ... voltage we are decreasing current which is advantageous. That's why transmission voltages is high.
Description : An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from ... C. any suitable ground to any available line lead D. any field pole to each field coil lead
Description : A voltmeter arranged across the power supply measures A. potential difference B. e.m.f C. current D. resistance
Last Answer : e.m.f
Description : Electric power is related to A. current in component B. potential difference C. electrical resistance D. both A and B
Last Answer : both A and B
Description : The filament of an electric lamp becomes white hot but the lead-in wires holding the filament are only slightly heated because they (a) have smaller current passing through them (b) have very low resistance (c) have higher melting point (d) are made of black iron
Last Answer : Ans:(b)
Description : Damp armature windings in a D.C. motor may lead to ____________. A. reduced voltage B. reduced current C. increased resistance D. overheating
Description : A bird sitting on a high tension electric wire does not get electrocuted because – (1) it has high resistance (2) the body is earthed (3) it does not form a closed path for the flow of current (4) its feet are good insulators
Last Answer : (3) it does not form a closed path for the flow of current Explanation: Electricity travels from a place of high voltage to low voltage, just as water travels from high elevation to low ... When electricity travels through a body in this fashion, electrocution takes place, and the bird can die.
Description : Nichrome wire is used in an electric heater because _______. (1) It has high resistance (2) It has high melting point (3) It can resist a current upto approx 5 amperes (4) For all of the above reasons
Last Answer : (4) For all of the above reasons
Description : Super conductors are substances that – (1) offer minimum resistance to flow of electric current (2) conduct electricity at low temperature (3) conduct electricity at high temperature (4) offer high resistance to the flow of electric current
Last Answer : (1) offer minimum resistance to flow of electric current Explanation: A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no ... is released from the material when it reaches the temperature at which it becomes superconductive.
Description : The fuse in our domestic electric circuit melts when there is a high rise in – (1) Inductance (2) Current (3) Resistance (4) Capacitance
Last Answer : (2) Current Explanation: In electronics and electrical engineering, a fuse is a type of low resistance resistor that acts as a sacrificial device to provide over protection, of either the load ... fuse interrupts excessive current (blows) so that further damage by overheating or fire is prevented.
Description : Super conductors are substances that (1) offer minimum resistance to flow of electric current (2) conduct electricity at low temperature (3) conduct electricity at high temperature (4) offer high resistance to the flow of electric current
Last Answer : offer minimum resistance to flow of electric current
Description : A bird sitting on a high tension electric wire does not get electrocuted because (1) it has high resistance (2) the body is earthed (3) it does not form a closed path for the flow of current (4) its feet are good insulators
Last Answer : it does not form a closed path for the flow of current
Description : A differential relay measures the vector difference between (a) two currents (b) two voltages (c) two or more similar electrical quantities (d) none of the above
Last Answer : (c) two or more similar electrical quantities
Description : Two transformers of identical voltages but different capacities are operated in parallel, for satisfactory load sharing: a) Impedances should be equal b) Per unit impedance must be equal c) per unit impedance and X/R ratio must be equal d) Impedance and X/R ratio must be equal
Last Answer : Ans: C
Description : When paralleling two alternators the synchronizing lamps grow dim and are totally darkened as the synchroscope pointer approaches the 0° position. This indicates the ____________. A. alternator voltages ... alternator is in phase with the bus voltage D. synchroscope pointer is defective or broken