Question paperElectrical Test Paper

Name :_____________________________________________Roll No-Institute:_____________________________________________Date :_____________________________________________

Note: Please tick ( ) whichever is appropriate according to you.Each question carries 1 markTime Duration : 30 mins

1What is Marshalling Kiosk in power transformer:a) It provides alarms, trips, controls and indications from main transformerc) It is the pressure device ruptures when temperature inside transformer increasesb) It is the base on which transformer rail is provided to pull and push transformerd)None of the above

2Factors on which soil resistance depends:a)depth of the electrodec)Naclb)moistured)all the above

3 Average resistance of human body is:a) 500 ohms c)1500 ohmsb)1000 ohms d)2000 ohms

4The cell which is used as standard cell is:a) Dry cellc) Mercury-Cadmium cell b) Solar cell d)Zinc-Carbon cell

5 The flux leakage coefficient in dc machine is usually:a)0.6 to 0.8c)1.1 to 1.3b)1.05d)2 to 2.5

6A DC series motor is best suited for electrical traction because:a) It develops high starting torquec) It is cheaper in costb) It runs at very high speedd)all the above

7The power factor of ac circuit lies betweena)0 and 1c)0 and -1 b) -1 and 1d) None of the above

8 In an induction motor when the air gap field between rotor and stator increases power factor of the machine:a) Increasesc) Does not have any effectb) Decreasesd) None of the above

9 The heat developed in an electric iron is attributed to __ powera)Apparent c)True b) Reactive d) True and reactive

10The rating of given on the name plate of a transformer indicates the:a)True power which it can supplyc)Apparent power which it draws from the supply mains b)Apparent power which it can supplyd)True power which it draws from the supply mains

11The color of fresh dielectric oil used in the transformer is:a)Dark brown c)Pale pinkb) Pale yellowd) White grey

12Maxwell's circulating current theorem:a)Utilizes Kirchhoff's voltage lawc)Is a network reduction methodb)Utilizes Kirchhoff's current lawd) Is confined to single loop circuits

13Annealing of metalsa)Removes internal stressesc) Increases the grain sizeb)Increases conductivityd) Both (a) and (b)

14Solder is an alloy ofa)Lead and tinc)Copper and Zincb)Aluminium and Copperd) Lead and Zinc

15A megger indicates infinity when test terminals are open-circuited. This is because:a) No current flows through the current coilc) No current flows through the compensating windingb)No current flows through the pressure coild)Current does not flow through current coil and pressure coil

16 A thermal protection switch is used to provide protection against:a)Over loadc) Short circuitb) Temperatured)Over voltage

17Arc chutes are used in:a) Oil circuit breakerc) SF6 circuit breakersb)Vacuum circuit breakersd)Air blast circuit breakers

18Impedance relays can be used for:a) Phase faults onlyc)Both earth and phase faultsb)Earth faults onlyd) None of the above

19Bundled Conductors are used for EHV transmission lines primarily for reducinga)Corona Lossc) Voltage drop across the lineb)Surge Impedance of the lined) I2R loss

20The pH value of the water used in boiler is:a)unityc)slightly less than sevenb)7d) slightly more than seven

21Three identical resistors are first connected in parallel and then in series. The resultant resistance of the first combination to the second will bea)9 times.c)3 timesb)1 / 9 timesd)1 / 3 times.

22When current flows through heater coil it glows but supply wiring does not glow becausea)supply wiring is covered with insulation layer.c)resistance of heater coil is more than the supply wires.b)current through supply line flows at slower speed. d)supply wires are made of superior materials

23Three 60 W bulbs are in parallel across the 60 V power line. If one bulb burns opena)there will be heavy current in the main line.c)all three bulbs will light.b)rest of two bulbs will not light.d)the other two bulbs will light.

24The maximum current rating for a 10 k, 0.5 W resistor isa)0.707 mA.c)14.14 mA.b)7.07 mA.d)28.28 mA.

25A 4 pole, 3 induction motor operated from a supply whose frequency is 50 Hz. What is the speed at which magnetic field of stator is rotatinga)1000 rpm.c)1440 rpm.b)500 rpm.d)1500 rpm.

26Neglecting the effects of stator resistance and leakage reactance, if the applied voltage is halved, then the developed torque in an induction motor will bea)Remain same.c)Decrease by factor of 2.b)Increase by a factor of 2.d)Decrease factor of 4.

27If rotor power factor of a 3 IM is 0.866, displacement between stator magnetic field and rotor magnetic field will bea)30.c)120. b)90.d)150.

28Which is a cold cathode lamp?a)Neon lamp. c)Mercury vapor lamp.b)Fluorescent lamp.d)Sodium vapor lamp.

29The incandescent bulbs rated respectively as P1 and P2 for operation at a specified main voltage are connected in series across the mains.Then the total power supplied by the mains to the two bulbsa)P1P2 / (P1 + P2).c)P1 + P2.b)(P12 + P22).d)( P1 P2).

30A 100 W light bulb burns on an average of 10 hours a day for one week. The weekly consumption of energy will bea)0.7 units.c)70 units. b)7 units. d)700 units.

31The voltages at the two ends of a line are 66 KV and its reactance is 30 . The capacity of the line isa)120 MW.c)250.5 MW.b)145.2 MW.d)350 MW.

32In any AC circuit alwaysa)reactive power is more than actual power.c)reactive power is more than apparent power.b)actual power is more than reactive power.d)apparent power is more than actual power.

33The power consumed in a circuit element will be least when the phase difference between the current and voltage isa)180 . c)60.b)90. d)0.

34The square waveform of current has following relation between rms value and average valuea)rms value of current is less than average value.c)rms value of current is greater than average value.b)rms value is equal to average value.d)None of the above

35If a sinosiodal wave has frequency of 50 Hz with 30A rms current. Which of the following equation represent this wave ?a)84.84 sin 25 t. c)60 sing 25t.b)42.42 sin 314 t. d)30 sin 50 t.

36An ideal synchronous motor has no starting torque becausea)rotor is made up of salient poles.c)relative velocity between the stator and rotor mmfs is zero.b)rotor winding is highly reactive.d)relative velocity between stator and rotor mmfs is not zero.

37A 4-pole generator with 16 coil has a two layer lap winding. The pole pitch isa)8c)16b)4d)32

38Guy wire is used toa)Support the polec) Provide emergency earth routeb) Provide protection against surges Protect conductors against short circuiting.

39Localization of cable faults done by a)short circuit tests.c)Varley loop tests.b)Murray loop tests.d)both B and C.

40Corona effect can be minimizeda)irregular surface of conductors.c)small spacing between conductors.b)stormy weather.d)large spacing between conductors.

AnswersGET - Electrical AnswersQ NoAnswerQ. No.Answer1a21b2d22c3b23d4c24b5c25d6a26d7a27c8b28a9c29a10b30b11b31b12a32d13d33b14a34b15a35b16a36c17d37a18c38a19a39d20d40d