Top electrical MCQ

1➤ Which of the following can produce maximum induced voltage?

1 A, 60 Hz AC current 1 A DC current 50 A DC current1 A, 490 Hz AC current

2➤ At resonant frequency, an R-L-C circuit draws maximum current due to the reason that

The voltage across the capacitor equals the applied voltageThe impedance is more than resistanceThe difference between capacitive reactance and inductive reactance is zeroThe power factor is less than unity

3➤ In dc machines, the air gap flux distribution in space at no load is

Flat toppedTriangularPulsatingRectangular

4➤ The errors mainly caused by human mistakes are A. . B. C. . D.

gross errorobservational errorsystematic error.instrumental error.

5➤ The smallest change in measured variable to which instrument will respond is .

accuracyprecisionresolutionsensitivity

6➤ Comparison methods are used

because they are expensive.when a high accuracy of measurement is requiredbecause they are most simple.because they take least time in measurement

7➤ Pendant holders are used in domestic installation, when the lamp is to be:

suspended verticallyfixed on wall fixed on boardfixed at an angle

8➤ If a DC series motor is started on no load, its speed will be:

Very smallNormalZeroEnormously high

9➤ The direction of magnetic lines of force around a straight current carrying conductor may be determined by:

Faraday's lawLenz's lawCork screw rule Fleming's left hand rule

10➤ The direction of magnetic lines of force is:

have no directionfrom N to S pole not fixed from S to N pole

11➤ Which material is used for making emitters in vacuum tubes?

carbonSulphurtungstenSilicon

12➤ Rectification efficiency and ripple factor of a full wave rectifier __________ and ______ respectively.

100 %, 0.482 91.6 %, 1.21 81.2 %, 0.48240.6 %, 1.21

13➤ The phenomenon of lagging of flux density behind the magnetizing force is called as

magnetic leakagemagnetic hysteresisrelative permeabilityMmf

14➤ A non-sinusoidal periodic waveform is free from DC component, cosine components and even harmonics. The waveform has

half wave and odd function symmetry.onty odd function symmetryonly half wave symmetry.half wave and even function symmetry

15➤ Which of the following methods is NOT used in the improvement of p.f. of a power network?.

Use of high p.f. equipmentHigh inductive elements in series with the loadsUse of synchronous capacitorsUse of static capacitors in parallel

16➤ Specific resistance of a conductor depends upon

resistance of the conductorboth A. and B.composition of conductor materialdimension of the conductor

17➤ The moving coil-meters, damping is provided by

eddy current diskdamping vane in the airtight chamberthe coil spring attached to the movingthe aluminium frame of the coil

18➤ Which of the following materials possess the least specific resistance? .

AluminiumSilverCopperIron

19➤ The scale of hot wire ammeter is

CrampedLinearNon LinearAbsolute linear.

20➤ The fractional slip of an induction motor is the ratio of

rotor cu-loss/stator cu lossrotor cu-loss/rotor outputstator cu-loss/stator inputrotor cu-loss/rotor input

Your score is