Description : Which of the following statements concerning AC circuits is correct? A. The power factor of a resistive circuit is always zero. B. True power in an inductive circuit always equals apparent power. ... . D. Total opposition to the flow of alternating current depends upon the amount of reactive power.
Last Answer : Answer: C
Description : The resistance in a magnetic material is called as a) Capacitance b) Inductance c) Reluctance d) Magnetic resistance
Last Answer : c) Reluctance
Description : The formula for computing impedance in a series circuit containing resistance, capacitance, and inductance is _____________. [ NOTE: the symbol * stands for 'multiplied by' ] A. Z = RT + XL + XC B. Z = R + XL - XC C. Z * Z = R * R + (XL - XC) * (XL - XC) D. Z = R * R + (XL * XC) - (XL * XC)
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.
Last Answer : Answer: A
Description : AC circuits develop resistance, inductance, and capacitance. The inductive reactance of a circuit is expressed in _____________. A. ohms B. mhos C. henrys D. farads
Description : AC circuits possess characteristics of resistance, inductance, and capacitance. The capacitive reactance of a circuit is expressed in _____________. A. ohms B. mhos C. henrys D. farads
Last Answer : Reluctance offered by the magnetic circuit depends upon nature of magnetic material, length of magnetic flux path, cross-sectional area of the material.
Description : Alternating current circuits develop resistance, inductance, and capacitance. The capacitance of individual capacitors is expressed in _____________. A. ohms B. mhos C. henrys D. farads
Last Answer : Answer: D
Description : Alternating current circuits develop resistance, inductance and capacitance. The inductance of a coil is expressed in _____________. A. ohms B. mhos C. henrys D. farads
Description : In AC Circuit Theory, the term that replaces the resistance is: w) inductance x) capacitance y) impedance z) reactance
Last Answer : ANSWER: Y -- IMPEDANCE
Description : The purpose of a short circuit forcing module (short time trip) installed in a branch line is to provide ____________. A. high speed clearance of low impedance short circuits in the branch B. ... C. isolation of short circuits by selective tripping of branch circuit breakers D. all of the above
Description : The function of the commutator in a DC motor is to ________. A. reverse the flow of current through the armature B. reverse the flow of current in the field poles C. reduce the reluctance of the magnetic path through the motor D. shift the neutral running plane of the brushes to prevent sparking
Description : 68 The path of a magnetic flux in a transformer should have A. High resistance B. High reluctance C. Low resistance D. Low reluctance
Last Answer : D. Low reluctance
Description : Non-inverting amplifier circuits have _______ (a) Very high input impedance (b) very low input impedance (c) low output impedance (d) none of above
Last Answer : (a) Very high input impedance
Description : Define reluctance and permeance with respect to magnetic circuit.
Last Answer : Reluctance: The opposition offered by magnetic circuit to establish magnetic flux in it, is called as “Reluctance”. Permeance: It is the reciprocal of reluctance and implies the magnetic core’s readiness with which magnetic flux is developed.
Description : Define the following terms: i) Magnetic flux density, ii) Reluctance, iii) Magneto-motive force, iv) Permeance.
Last Answer : (i) Magnetic flux density (B): It is the magnetic flux per unit area measured at right angles to the flux path. (Its unit is weber/m2 or tesla). (ii) Reluctance: It is the ... flux to set up through it and it is reciprocal of reluctance. Permeance = 1/ Reluctance. Unit: weber/ampere.
Description : When reading electrical motor controller diagrams, it helps to know that ____________. A. current paths in the control circuit are drawn as heavy lines and in the power circuit as lighter lines B. current ... subject to 500 volts or greater are drawn as light lines and below 500 volts as heavy lines
Last Answer : Answer: B
Description : Three factors responsible for the change in voltage as load is applied to an AC generator are: 1) the drop in resistance in the armature circuit, 2) the change in flux, and 3) the ____________. A. armature winding speed B. inductance load drop C. coil pitch factor D. armature reactance voltage drop
Description : Capacitance is the property of an electric circuit opposing a change in the _____________. A. current in the circuit B. voltage in the circuit C. inductance in the circuit D. resistance in the circuit
Description : In a series circuit, which value will remain unchanged at all places in the circuit? A. Voltage B. Current C. Resistance D. Inductance
Description : The illustrated circuits are used to measure ___________. EL-0024 A. resistance B. gauss or magnetic field strength C. battery discharge rate in Amp-hours D. current
Description : Operational amplifiers, used primarily in analog circuits, are characterized by ____________. A. high input impedance, high gain and low output impedance B. high input impedance, high gain and high output ... gain and high output impedance D. low input impedance, high gain and low output impedance
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 electrical properties listed will always be the same for each component in a parallel circuit? A. Impedance B. Current C. Resistance D. Voltage
Description : The combined effect of inductive reactance, capacitive reactance, and resistance in an AC series circuit is known as _____________. A. reactance B. total reactance C. impedance D. resonance
Description : When troubleshooting electronic equipment, you should use a high impedance multimeter ________________. A. to prevent excess current flow through the meter that would damage it B. for AC measurements only ... being tested D. so as not to load down the circuit and obtain erroneous voltage readings
Description : Give equivalent resistance, reactance and impedance referred to secondary circuit.
Last Answer : Req = R2 +R1' = R2+ R1'/a² Xeq = X2 +X1' = X2+ X1'/a² Zeq = Z2 + Z1' = Z2+ Z1'/a² where a=T1/T2
Description : Give equivalent resistance, reactance and impedance referred to primary circuit.
Last Answer : Req = R1 +R2' = R1+a² R2' Xeq = X1 +X2' = X1+a² X2' Zeq = Z1 +Z2' = Z1+a² Z2' where a=T1/T2
Description : When working on electrical circuits containing large capacitors, in addition to deenergizing the circuit, which of the listed precautions should also be taken? A. Keep all radio equipment ... capacitor insulation resistance. C. Ground the capacitor terminals. D. Check capacitor circuit polarity.
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
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 : The use of four diodes, in a full-wave bridge rectifier circuit, will __________. A. provide unidirectional current to the load B. allow a very high leakage current from the load C. convert direct current to alternating current D. offer high opposition to current in two directions
Description : Which of the following are the constants of the transmission lines ? (a) Resistance (b) Inductance (c) Capacitance (d) All of the above
Last Answer : (d) All of the above
Description : The basic control action of a magnetic amplifier depends upon _____________. A. variations in the load capacitance B. changes in inductance C. type of core material D. construction of the core
Description : What is the velocity factor of coaxial cable with a characteristic impedance of 50Ω and capacitance of 30pF/ft and inductance of 75 nH/ft? A. 0.58 B.0.68 C. 0.98 D. 0.81
Last Answer : B.0.68
Description : Referred to the dielectric constant of a transmission line material. A. Inductance and capacitance B. Velocity factor C. Characteristic impedance D. Propagation velocity
Last Answer : B. Velocity factor
Description : 43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses
Last Answer : C. Decrease the reluctance of the magnetic path
Description : What is the SI unit for magnetic reluctance? A) Ampere B) Ampere-turns per weber C) Henry D) None of these
Last Answer : What is the SI unit for magnetic reluctance? A) Ampere B) Ampere-turns per weber C) Henry D) None of these
Last Answer : The magnetic reluctance of a material decreases with increasing cross-sectional area of the material.
Description : Transmission lines when connected to antenna have A. capacitive load B. resistive load whose resistance is less than characteristics impedance C. resistive load at the resonant frequency D. resistive load whose resistance is greater than the characteristic impedance of the line
Last Answer : C. resistive load at the resonant frequency
Description : Handheld phase sequence indicators are useful when ________. A. preparing to parallel alternators B. connecting lighting branch circuits C. troubleshooting DC motors D. connecting shore power lines to the ship
Description : An open coil in a transformer will be indicated by which of the listed conditions? A. 'zero' resistance accompanied by high inductance B. no resistance accompanied by stray inductance C. infinite resistance in addition to no inductance D. infinite resistance in addition to normal inductance
Description : The Wheatstone bridge is a precision measuring instrument utilizing the principle of changes in _____________. A. inductance B. capacitance C. resistance D. amperage
Description : Hays bridge is used to measure___________ and Schering bridge is used to measure____________ a) Inductance, Inductance b) Inductance, Capacitance c) Capacitance, Inductance d) Resistance, Capacitance
Last Answer : Ans: Inductance, Capacitance
Description : In the illustration, the component labeled 'EXC' is _______. EL-0003 A. a separate class II regulated DC generator for critical direct current loads B. a generator feeding the FLD ... to drive the governor for turbogenerator speed. D. the electronic driver for the switchboard metering circuits
Description : The voltage output of an AC generator is accurately controlled by _____________. A. changing the sensitivity of the prime mover to large changes in voltage B. varying the reluctance of the air gap C. varying the DC exciter voltage D. shorting out part of the armature windings
Description : What is reluctance?
Last Answer : It is the property of a magnetic material, which opposes the establishment of magnetic flux in it, as in the case resistance in an electric circuit.
Description : Inductance is the property of an electric circuit that _____________. A. opposes any change in the applied voltage B. opposes any change in the current flow through the circuit C. aids any changes in the applied voltage D. aids any changes in the current through the circuit
Description : Which of the following characteristics is most critical in determining the size of the cable to be used in a particular circuit? A. voltage rating B. weight per unit length C. current rating D. inductance per unit length