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
Last Answer : Answer: C
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
Last Answer : Answer: B
Description : In series RLC circuit at resonant a) Voltage is in phase with current b) Current is maximum c) Inductive reactance = Capacitive reactance d) All of the above
Last Answer : Ans: All of the above
Description : An AC circuit has a capacitive reactance of 30 ohms in addition to an inductive reactance of 40 ohms connected in series. What is the reactance of the circuit? A. 8.37 ohms B. 10.00 ohms C. 50.00 ohms D. 70.00 ohms
Description : An AC circuit has capacitance arranged in series. If the line voltage remains constant, the capacitive reactance value can be varied by changing the _____________. A. line frequency B. resistance C. number of commutating poles D. number of interpoles
Last Answer : Answer: A
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
Last Answer : Answer: D
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
Description : What is the reactance property at the input of a shorted quarter wavelength line? A. A parallel LC circuit B. A pure inductive reactance C. A series LC circuit D. A pure capacitive reactance
Last Answer : A. A parallel LC circuit
Description : Series capacitors are used to (a) compensate for line inductive reactance (b) compensate for line capacitive reactance (c) improve line voltage (d) none of the above
Last Answer : (a) compensate for line inductive reactance
Description : Battery capacities are given in _____________. A. volts B. volt-amperes C. volt-hours D. ampere-hours
Description : The inductance of a coil is measured in _____________. A. ohms B. volts C. henries D. amperes
Description : Power transformers are rated in _____________. A. kilowatts B. ampere-turns C. kilowatt-volts D. kilovolt-amperes
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.
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 : The unit of apparent power in a purely inductive circuit is called the _____________. A. kva B. var C. emf D. watt
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 : A three-phase alternator operates at 450 volts with a power factor of 0.8. If the ammeter indicates 250 amperes, what should be the KW meter reading? A. 90.00 KW B. 127.27 KW C. 155.70 KW D. 194.85 KW
Description : Define: (i) Inductive reactance (ii) Impedance.
Last Answer : i) Inductive reactance: Inductive reactance is the opposition offered by an inductor to alternating current . It is denoted by XL and given by XL = 2πf LΩ = ωL Ω ii)Impedance: It is the total opposition offered to flow of AC current in an AC circuit. It is denoted by Z and the unit is ohm.
Description : The component labeled 'CR1' in the circuit shown in the illustration __________________. EL-0085 A. varies its anode/cathode polarity depending on 'RL' current B. rectifies the varying voltage from the ... reactance to smooth ripple D. establishes a constant reference voltage for the base of 'Q1'
Description : A series combination of resistance 100 ohm and capacitance 50µf is connected in series to a 230 V, 50HZ supply. Calculate (i) Capacitive reactance (ii) Current (iii) Power factor (iv) Power consumed
Last Answer : For RC series circuit
Description : Voltage will always lead current in a/an ______________. A. capacitive circuit B. inductive circuit C. magnetic circuit D. resistive circuit
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 : 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 : 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 : 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
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 : 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 : An electrical component is connected across a 120 volt 60 hertz AC supply. What is the current drawn by the component if the impedance is 200 ohms? A. 0.01 amperes B. 0.60 amperes C. 1.67 amperes D. 100 amperes
Description : In an AC circuit, the inductive reactance of a coil varies with the _______________. A. resistance of the circuit B. frequency of the circuit C. voltage of the circuit D. current of the circuit
Description : In the illustrated circuit, one advantage of the capacitor coupling over direct coupling is ____________. EL-0048 A. as the frequency decreased the capacitive reactance (Xc) increases B. the amplifier becomes ... of the signal while it isolates the biasing of each stage. D. good frequency response.
Description : What is capacitance and capacitive reactance?
Last Answer : Capacitance The property of a capacitor to store electrical energy in it, when it is connected to an electric supply is called capacitance. Unit for measurement is farad. Capacitor store an electric ... called capacitive reactance and it denoted by the letter XC. The unit for measurement is ohm.
Description : Which of the following statements describes what will occur if the motor shown in the illustration is required to carry 150% of full load? EL-0056 A. The primary counter emf will be increased. B. ... slip will decrease. D. The slip value, stator current curve, and torque curve will all coincide.
Description : The electrical diagram shown in the illustration is used to depict a/an ____________. EL-0015 A. resistance circuit B. inductive circuit C. stepdown circuit D. capacitive circuit
Description : What is the power factor in pure resistive , capacitive , inductive load ?
Last Answer : Answer : Power factor cosΦ = 1 in pure resistive load, cosΦ = 0 in capacitive load , cosΦ = 0 in inductive load .
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 : A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf? (A) 100 Volts. (B) 0.1 Volts. (C) 1 Volts. (D) 10 Volts.
Last Answer : Ans: D Given N = 1500 rpm, Φ = 0.4 mWb, Z = 1000, P = 4, & A= 4 Therefore, Eb = NΦPZ / 60 A = 1500 x 0.4 x 4 x 1000 x 10^-3 / 60 x 4 = 60/6 = 10 volts
Description : Although saturable reactors are extremely useful in some applications, their gain is low because of ____________. A. core hysteresis losses B. inductive reactance in the control winding C. IR drop throughout the load winding D. all of the above
Description : The purpose of the capacitor within component 'B' of the circuit shown in the illustration is to ____________. EL-0081 A. prolong the life of the component's contacts B. discharge the neon within ... the inductive reactance in the circuit D. store power to operate the circuit should 'D' open
Description : What is inductance and inductive reactance?
Last Answer : Inductance A coil carrying alternating current produces an alternating flux, which causes to link with same coil and produces an emf in the coil, which opposes the applied emf. This property is known ... is known as inductive reactance and denoted by the letter XL. The unit for measurement is ohm.
Description : Capacitors can be used in electric distribution systems to improve power factor. This is accomplished by seesawing energy between the capacitor and the _____________. A. generator B. inductive loads C. resistive loads D. all of the above
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 : 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 : The force that causes free electrons to move in a conductor as electric current flow is called a/an _____________. A. resistant force B. electromotive force C. inductive force D. dielectric force
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 : In a series wound motor, the current passing through the field windings is also passing through the _____________. A. armature B. shunt field C. reactance comparator D. laminations
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 : What is impedance and reactance diagram?
Last Answer : The impedance diagram is the equivalent circuit of power system in which the various components of power system are represented by their approximate equivalent circuits. The impedance diagram is ... ddiagram can be obtained from impedance diagram if all the resistive components are neglected.
Description : Two transformers operating in parallel will share the load depending upon their (A) Rating. (B) Leakage reactance. (C) Efficiency. (D) Per-unit impedance.
Last Answer : Ans: A Transformers having higher kVA rating will share more load.
Description : A three-phase synchronous motor has a terminal voltage of 460 V and a terminal current of 120 A at a power factor of 0.95 lagging, synchronous reactance of 1.68 ohm and the field current is 47 A. The field to armature mutual ... _____________. (a). 20mH (b). 16mH (c). 24mH (d). 22mH
Last Answer : 22