0% 0 Electrical Engineering Quiz 10 1 / 50 Which of the following statements is correct ? Electrolytic capacitors must be connected in correct polarity Air capapitors have a black band to indicate the outside foil Ceramic capacitors must be connected in correct polarity Mica capacitors are available in capacitance values of 5 to 20 uF 2 / 50 Compensating windings are used in D.C. generators______________? mainly to reduce the eddy currents by providing local short-circuits to provide path for the circulation of cooling air to neutralise the cross-magnetising effect of the armature reaction none of the above 3 / 50 The circuit that provides the best stabilization of operating point is___________________? Base resistor bias Collector feedback bias None of the above Potential divider bias 4 / 50 At room temperature, an intrinsic silicon crystal acts approximately as_______________? An insulator A battery A conductor A piece of copper wire 5 / 50 Which of the following is not necessarily an advantage of interconnecting various power stations? Economy in operation of plants Increased reliability Improved frequency of power supplied Reduction in total installed capacity 6 / 50 The core of a coil has a length of 200 mm. The inductance of coil is 6 mH. If the core length is doubled, all other quantities, remaining the same, the inductance will be_____________? 48mH 12 mH 24mH 3 mH 7 / 50 Piezoelectric materials serve as a source of ____________ ? ultrasonic waves microwaves resonant waves musical waves 8 / 50 The diode detector in an AM radio receiver is usually found _____________? Before the first RF stage None of the above After the first RF stage After several stages of amplification 9 / 50 Armature reaction in dc motor results___________? decrease in speed open circuit increase in speed short circuit 10 / 50 The form factor is the ratio of_______? r.m.s. value to average value peak value to r.m.s. value none of the above average value to r.m.s. value 11 / 50 As the load is applied to a synchronous motor, the motor takes more armature current because the rotor by shifting its phase backward causes motor to take more current the increased load has to take more current the rotor strengthens the rotating field casuing more motor current the back e.m.f. decreases causing an increase in motor current 12 / 50 A synchronous condenser is virtually which of the following? Induction motor Over excited synchronous motor Under excited synchronous motor D.C. generator 13 / 50 Operating point represents__________________? The magnitude of signal None of the above Zero signal values of IC and VCE Values of IC and VCE when signal is applied 14 / 50 If the crystal frequency changes with temperature, we say that crystal has___________temperature coefficient? Negative Positive None of the above Zero 15 / 50 To reverse the direction of rotation of acapacitor start motor while it is running we should___________? reverse the direction of connections of the auxiliary winding and immediately connect it to supply disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding reverse the direction of connection of the auxiliary winding and after motor comes to rest then connect auxiliary winding to the supply disconnect motor from supply and immediately reconnect it to supply with reversed connections of the main winding 16 / 50 The approximate input impedance of the opamp circuit which has Ri=10k, Rf=100k, RL=10k? 120k ? 110k 10k 17 / 50 The phenomenon of an uncharged body getting charged merely by the nearness of a charged body is known as____________? chemical effect induction pholoelectric effect magnetic effect 18 / 50 The conduction losses in IGBT is____________? Lower than that of MOSFET Equal to that of BJT More than that of MOSFET Equal to that of MOSFET 19 / 50 The principle on which vector voltmeter is based is_____________? that it measures the response of linear ramp voltage that it works on the principle of complex variation same as digital meter that it measures the amplitude of a single at two points and at the same time measures their phase difference 20 / 50 The current zero interruption, in oil and air blast circuit breakers, is achieved by_______________? deionizing the oil with forced air lengthening of the gap cooling and blast effect All 21 / 50 A pilot exciter is provided on generators for which of the following reasons? To provide requisite starting torque to generator None of the above To excite the poles of main exciter To provide requisite starting torque to main exciter 22 / 50 The arrow in the symbol of a transistor indicates the direction of____________? hole current in the emitter donor ion current electron current in the emitter electron current in the collector 23 / 50 In D.C. machines the usual limit of slot pitch is________________? between 25 to 35 mm between 5 to 10 mm between 15 to 20 mm between 10 to 15 mm 24 / 50 A field of force can exist only between_____________? two ions two metal particles two molecules two atoms 25 / 50 A switchgear is device used for_____________? switching an electrical circuit 111. interrupting an electrical circuit switching, controlling and protecting the electrical circuit and equipment switching and controlling an electrical circuit 26 / 50 Quadrilateral speed-time curve pertains to which of the following services ? Main line service Sub-urban service Urban service Urban and sub-urban service 27 / 50 In a lamp load when more than one lamp are switched on the total resistance of the load_____________? increases decreases none of the above remains same 28 / 50 The equation of 50 Hz current sine wave having r.m.s. value of 60 A is____________? 42.42 sin 314 t 60 sin 25 t 84.84 sin 3141 60 sin 50 t 29 / 50 The area under a load curve gives__________? none of the above maximum demand energy consumed average demand 30 / 50 The speed of a universal motor is usually reduced by using____________? gearing brakes belts chains 31 / 50 In D.C. motor which of the following can sustain the maximum temperature rise? Commutator Slip rings Field winding Armature winding 32 / 50 Which of the following statement is correct_______________? A semi-conductor is a material whose conductivity is same as between that of a conductor and an insulator A semi-conductor is a material made of alternate layers of conducting material and insulator A semi-conductor is one which con?ducts only half of the applied voltage A semi-conductor is a material which has conductivity having average value of conductivity of metal and insulator 33 / 50 ___________ is invariably used as base load plant. Gas turbine plant Pumped storage plant Diesel engine plant Nuclear power plant 34 / 50 Differential amplifiers are used in______________? Voltage followers Instrumentation amplifiers Voltage regulators Buffers 35 / 50 A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will_____________? will be of 5 Hz will be zero will be of 5 xiVHz will be of v Hz 5 36 / 50 In capacitor start single-phase motors____________? none of the above current in the starting winding is in phase with voltage in running winding current in the starting winding lags the voltage current in the starting winding leads the voltage 37 / 50 capacitors are used in transistor circuits? Paper Ceramic Air Electrolytic 38 / 50 In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when_______________? the generator runs on overload the generator runs on full load there is no load on|he generator the generator runs on designed speed 39 / 50 Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it___________? leads to their increased weight produces fringing increases their cost of manufacture lowers their power efficiency 40 / 50 The power loss is an important factor for the design of_______________? motor generator transmission line feeder 41 / 50 Addition of trivalent impurity to a semiconductor creates many_______________? Free electrons Valence electrons Bound electrons Holes 42 / 50 By which of the following methods string efficiency can be improved? Any of the above Using a guard ring Using long cross arm Grading the insulator 43 / 50 In order to get more voltage gain from a transistor amplifier, the transistor used should have_________________? None of the above Wide emitter Thin collector Thin base 44 / 50 The internal resistance of a 20,000 ohm/volt voltmeter set on its 5 V range is_____________? 200,000 ? 20,000 ? 100,000 ? 1,000,000 ? 45 / 50 In a ceilingfan employing capacitor run motor____________? secondary winding surrounds the primary winding primary winding surrounds the secondary winding both are usual arrangements none of the above 46 / 50 The value of co-efficient of adhesion will be high when rails are_________________? greased wet cleaned with sand sprayed with oil 47 / 50 For both lap and wave windings, there are as many commutator bars as the number of_____________? slots poles armature conductors winding elements 48 / 50 The values of h parameter of a transistor in CE arrangement are ____________ arrangement? The same as for CC Different from that in CB None of the above The same as for CB 49 / 50 We use _____________ ICs in computers? None of the above Linear Digital Both digital and linear 50 / 50 The draught in locomotive boilers is produced by_____________? chimney forced fan only motion of locomotive steam jet 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 9 Electrical Engineering Quiz 11Next
