0% 0 Electrical Engineering Quiz 40 1 / 50 In a 3 phase VSI out of eight valid states, the number of valid states that produce zero ac line voltages is/are_________? two One Three Four 2 / 50 The term ?cogging? is associated with___________? induction motors D.C. series motors compound generators three phase transformers 3 / 50 In a pure resistive circuit__________? current can lead or lag the voltage by 90? current leads the voltage by 90? current is in phase with the voltage current lags behind the voltage by 90? 4 / 50 An amplifier without feedback has a voltage gain of 50,input resistance os 1 K? & Output resistance of 2.5K?.The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback factor of 0.2 is___________? 1/5K? 5K? 1/11K? 11K? 5 / 50 The delay fuses are used for the protection of ___________? light circuits motors power outlet circuits fluorescent lamps 6 / 50 If an ohmmeter reading immediately goes practically to zero and stays there, capacitor is___________? short-circuited satisfactory charged lossy 7 / 50 Dynamic equalising circuit is useful____________? To limit di / dt of SCR To limit dV / dt of SCR For voltage equalisation Both B and C 8 / 50 For which of the following protection from negative sequence currents is provided ? Transmission line Motors Transformers Generators 9 / 50 A current amplification of 2000 is a gain of_________________? 3 db 200 db 66 db 20 db 10 / 50 The most suited gate pulses given to the AC regulator with R ? L load can be in the form of____________? Continuous signal None of these A train of pulses Large isolating pulse transformer 11 / 50 A switch has ______________? Two states Three states One state None of the above 12 / 50 The motor used on small lathes is usually_________? single-phase capacitor run motor D.C. shunt motor universal motor 3-phase synchronous motor 13 / 50 Dielectric strength of medium____________? none of the above increases with rise in temperature increases with moisture content is same for all insulating materials 14 / 50 In a synchronous motor, the magnitude of stator back e.m.f. & depends on_______________? load on the motor d.c. excitation only speed of the motor both the speed and rotor flux 15 / 50 For an overhead line, the surge impedance is taken as________________? 20-30 ohms 70?80 ohms 100?200 ohms 500?1000 ohms 16 / 50 Fleming?s right-hand rule regarding direction of induced e.m.f., correlates__________? magnetic field strength, induced voltage and current magnetic flux, direction of force and direction of motion of conductor magnetic flux, direction of current flow and resultant force magnetic flux, direction of motion and the direction of e.m.f. induced 17 / 50 In CE arrangement, the value of input impedance is approximately equal to ______________? Hie Hoe Hre None of the above 18 / 50 The surge resistance of cable is__________? 5 ohms 50 ohms 100 ohms 20 ohms 19 / 50 The ac voltage controller can be used for ___________? On ? line transformer tap changing Lighting and heating control All of these Soft starting 20 / 50 Very large values of modulation index (greater than 3.24) lead to___________? Trapezoidal AC output voltage Sine AC output voltage Triangular AC output voltage Square AC output voltage 21 / 50 Which of the following can be measured by the use of a tachogenerator ? Speed Speed and acceleration Acceleration Displacement 22 / 50 Magnetic field in a D.C. generator is produced by_______________? permanent magnets none of the above electromagnets All 23 / 50 Murray loop test can be used for location of________________? ground fault on a cable short circuit fault on a cable none of the above both the ground fault and the short-circuit fault 24 / 50 The rupture of co-valent bonds will occur when the electric field is__________________? 6 V/cm 1000 V/cm 100 V/cm More than 105 V/cm 25 / 50 The length cf air gap to be provided in __________ is primarily determined by power factor consideration? induction motor synchronous motor d.c. series motor . d.c. shunt motor 26 / 50 Effect of moisture on the insulating materials is to________________? decrease insulation resistance all of the above decrease dielectric constant decrease dielectric strength 27 / 50 An emitter follower has ______________input impedance? High Zero Low None of the above 28 / 50 Electric current passing through the circuit produces_____________? thermal effect all above effects magnetic effect luminous effect 29 / 50 Conductance : mho :: ____________? inductance : farad capacitance : henry resistance : ohm lumen : steradian 30 / 50 Capacitive susceptance is a measure of__________? the extent of neutralisation of reactive power in a circuit reactive power in a circuit a purely capacitive circuit?s ability to pass current a purely capacitive circuit?s ability to resist the flow of current 31 / 50 Basically a potentiometer is a device for________________? measuring a current comparing two voltages measuring a voltage comparing two currents 32 / 50 The series field of a short-shunt D.C. generator is excited by_______________? armature current shunt current external current load current 33 / 50 The cathdde voltage drop, in a mercury arc rectifier, is due to_____________? surface resistance expenditure of energy in overcoming the electrostatic field expenditure of energy in liberating electrons from the mercury expenditure of energy in ionization 34 / 50 A Weston frequency meter is_____________? moving coil instrument none of the above moving iron instrument dynamometer instrument 35 / 50 In a transistor if ? = 100 and collector current is 10 mA, then IE is___________? 110 mA none of the above 100 mA 100.1 mA 36 / 50 When V is the applied voltage, then the breakdown torque of a synchronous motor varies as_________? V V312 V2 1/V 37 / 50 The power demand can be estimated approximately by____________? Mathematical method Statistical method Load survey method Economic parameters 38 / 50 method has leading power factor____________? Dielectric heating Resistance heating Arc heating Induction heating 39 / 50 Two charges are placed at a certain distance. If the magnitude of each charge is doubled the force will become_____________? 1/8th of its original value 1/4th of its original value 4 times of its original value 8 times of its original value 40 / 50 Voltage Series feedback also called series-shunt feedback) results in__________? Decreases in both input & output impedances Decrease in input impedance & increase in output impedance Increase in input impedance & decreases in output impedance Increase in both input & output impedances 41 / 50 The lead-acid cell should never be discharged beyond____________? 1.8 V 2 V 2.1 V 1.9 V 42 / 50 On which of the following voltage range settings will a voltmeter present the minimum load on a circuit? 50 V 500 V 1 V 1,000 V 43 / 50 1 db corresponds to_____________change in voltage or current level? 25% 40% 20% 80% 44 / 50 A series resonant band-pass filter consists of a 2 mH coil, a 0.005 ?F capacitor, and a 120 ? resistor. The winding resistance of the coil is 12 ?. The output voltage is taken off the resistor. Input voltage is 12 Vrms. What is the output voltage magnitude at the center frequency (f0)? 1.1 V 10.9 V 12 V 1.09 V 45 / 50 When a transistor is driven to cut off, ideally the output is _______________? VCC/3 0 VCC/2 VCC 46 / 50 The maximum a.c. power output from a class A power amplifier is 10 W. What should be the minimum power rating of the transistor used ? 5 W 15 W 10 W 20 W 47 / 50 The input resistance of a VTVM is about ______________? 1000 O 20 kO 10 MO 10 kO 48 / 50 A fuse is never inserted in____________? neutral wire phase dine negative of D.C. circuit positive of D.C. circuit 49 / 50 Power amplifiers generally use transformer coupling because transformer permits______________? Good frequency response Distortionless output Cooling of the circuit Impedance matching 50 / 50 need frequent starting and stopping of electric motors ? Air-conditioners Lifts and hoists Paper mills Grinding mills Provide Your Information Your score is The average score is 0% LinkedIn Facebook Twitter 0% Restart quiz Send feedback Share on facebook Facebook Share on twitter Twitter Share on whatsapp WhatsApp PrevElectrical Engineering Quiz 39 Electrical Engineering Quiz 41Next
