Tricky electrical MCQ

1➤ Power factor meters have: -

Only voltage coiOnly current coilBoth current and voltage coilOnly inductive voltage coil

2➤ Three 60 W bulbs are in parallel across the 60 V power line. If one bulb burns open: -

All three bulbs will light.The other two bulbs will light.Rest of the two bulbs will not lightThere will be heavy current in the main line

3➤ In context of corona, if the conductors are polished and smooth, which of the following statement is correct? (A) (B) (C) (D)

Corona glow will not occurPower loss will be least Hissing sound will be more intense Corona glow will be uniform along the length of the conductor

4➤ The coils of DC motor starter are wound with wire of…..

KanthalNichromeCopperManganin

5➤ Fault diverters are basically _________

Fast switchesCircuit breakersFusesRelays

6➤ In electric motor coding; TEFC means

Tough energy fan codedThermal energy fan cooledTotally enclosed fan cooledTotal efficient fan coded

7➤ Which of the following is NOT correct for series resonance circuit?

It is also known as rejector circuit.The power factor is unityIt magnifies the voltage across inductor Impedance at resonance is minimum

8➤ Metals approach super-conductivity conditions: - (A) (B) (C) (D)

near critical temperaturenear absolute zero temperatureat triple pointunder the conditions of high temperature and pressure

9➤ In a nickel-cadmium-alkali cell the electrolyte is

zinc chlorideammonium chloride.potassium hydroxide Sulphur acid

10➤ A transistor (BJT) works as a variable resistance when: -

Emitter junction is forward biased and collector junction is reverse biasedEmitter junction is reverse biased and collector junction is forward biased Emitter junction is forward biased and collector junction is forward biasedEmitter junction is reverse biased and collector junction is reverse biased

11➤ A buck converter is used to: -

Step up the voltage Step down the voltageStabilize the voltageExactly double the voltage

12➤ In LC transistor oscillator, the active component used is: -

TransistorResistorCapacitorInductor

13➤ Identify the false statement.

Arsenic is a donor impurityResistivity of the semiconductor is in the order of 10-3 Ω cmSilicon and germanium are semiconductorsIndium is an acceptor impurity

14➤ Which of the following material is a insulator?

Dry Air GraphiteWaterNone of the above

15➤ Which of the following semiconducting components is used in photoconductive devices?

Zinc oxideBarium oxideCadmium sulphideCaesiumantimode

16➤ Which among the following metals has maximum Curie temperature?

GadoliniumIronDysprosiumNickel

17➤ Fill in the blank(s) with the correct option: According to IE rules, 1956 low voltage is where the voltage does not exceed ________.

550 V 650 V350 V250 V

18➤ In this method by injecting voltage at slip frequency in the rotor circuit, the speed of an induction motor can be changed. Determine the method mentioned in the context.

Speed controlSecondary foreign voltage controlRotor resistance controlVoltage control

19➤ In which of the following cases, MOSFET helpful? I) Switch for LED II) Switch with hysteresis III) Switching solenoid

I, II, III Switch with hysteresis Switching solenoidSwitch for LED

20➤ Name the motor which carries a single-phase exciting winding which is similar to the main winding of a single-phase induction motor that carries a distributed DC type winding.

DC shunt MotorCompound motorRepulsion motorDC series motor

21➤ Identify the incorrect statements from the given options regarding the characteristics of a magnetic circuit.

Permeance is analogous to conductanceReluctance is analogous to resistanceFlux is analogous to potential differenceMagnetomotive force is analogous to voltage

22➤ What is the average value of a whole sinusoidal waveform over one complete cycle? A

0264

23➤ The point form of Ampere's Law is given by

Curl (H) = J Curl (D) = JCurl (V)=1Curl (B) = 1

24➤ The equivalent circuit of a zener diode consists of

A small dynamic resistance in series with DC batteryA capacitance in series with current source A capacitance in series with DC batteryA resistance in parallel with DC battery

25➤ Select incorrect statement for N-P-N transistor.

In a N-P-N transistor, majority charge carrier are electronsEmitter arrow shows direction of flow of conventional currentIn a N-P-N transistor, majority charge carrier are holesMobility of electrons is higher than that of holes

26➤ What is the range of length for a medium transmission line? .

60 km to 150 km150 km to 200 km30 km to 60 km 10 km to 30 km

27➤ Identify the conductor that is used to electroplate printed circuits and communications equipment.

RhodiumSilverAluminiumCopper

28➤ Which statement is correct in case of ideal OPAMP?

zero input impedance and infinite output impedancezero input impedance and zero output impedance Infinite input impedance and infinite output impedanceInfinite input impedance and zero output impedance

29➤ A Hartley Oscillator is used for generating

Audio frequency oscillationMicrowave oscillationRadio frequency oscillationVery low frequency oscillation

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