# ELECTRICAL ENGINEERING IMPORTANT MCQ-BASIC ELECTRICAL PART ONE

**ANSWER KEY-Correct answer is indicated by symbol (V) in options.**

**HINTS-In some questions options E-HINTS is indicating the hints of answer.**

1) Resistivity of a wire depends on

A [ ]) length

**B [v]) material**

C [ ]) cross section area

D [ ]) none of the above

2) If 1 A current flows in a circuit, the number
of electrons flowing through this circuit is

A [ ]) 1.6 × 1019

**B [v]) 0.625 × 1019**

C [ ]) 1.6 × 10 - 19

D [ ]) 0.625 × 10 - 19

3) The resistance of a conductor of diameter d
and length l is R Ω. If the diameter of the

conductor is halved and its length is doubled,
the resistance will be

A [ ]) R Ω

B [ ]) 2R Ω

C [ ]) 4R Ω

**D [v]) 8R Ω**

4) How many coulombs of charge flow through a
circuit carrying a current of 10 A in 1

minute?

A [ ]) 10

B [ ]) 60

**C [v]) 600**

D [ ]) 1200

5) The unit of resistivity is

A [ ]) Ω.

**B [v]) Ω - metre.**

C [ ]) Ω / metre.

D [ ]) Ω / m².

6) Instantaneous power in inductor is
proportional to the

**A [v]) product of the instantaneous current and rate of change of current.**

B [ ]) square of instantaneous current.

C [ ]) square of the rate of change of current.

D [ ]) temperature of the inductor.

7) The voltage induced in an inductor is
represented as,

A [ ]) product of its inductance and current
through it.

B [ ]) ratio of its inductance to current through
it.

C [ ]) ratio of current through it to its
inductance.

**D [v]) product of its inductance and rate of change of current through it.**

8) Magnetic flux has the unit of

A [ ]) Newton

B [ ]) Ampere turn

**C [v]) Weber**

D [ ]) Tesla

9) If P is the power of a star connected system
then what will be power of an equivalent

delta connected system?

**A [v]) P**

B [ ]) 3P

C [ ]) P/3

D [ ]) None of the above

10) Which of the followings is/are active
element?

A [ ]) Voltage source

B [ ]) Current source

**C [v]) Both**

D [ ]) None of these.

11) Which of the following are the passive
elements?

A [ ]) Resistor

B [ ]) Bulb

**C [v]) Both**

D [ ]) None of these.

12) Power dissipation in ideal inductor is

A [ ]) Maximum

**B [v]) Zero**

C [ ]) Minimum

D [ ]) A finite value

13) Inductor does not allow the sudden change of

**A [v]) current**

B [ ]) voltage

C [ ]) power

D [ ]) None of the above

14) Capacitor does not allow the sudden change of

A [ ]) current

**B [v]) voltage**

C [ ]) power

D [ ]) None of the above

15) Internal resistance of ideal voltage source
is

**A [v]) zero**

B [ ]) infinite

C [ ]) finite

D [ ]) 100 ohms

16) Internal resistance of ideal current source
is

A [ ]) zero

**B [v]) infinite**

C [ ]) finite

D [ ]) 100 ohms

17) Which quantity consists of a unit KWh ?

**A [v]) Energy**

B [ ]) Time

C [ ]) Power

D [ ]) Charge

18) Which of the following has no units?

A [ ]) Permeability

B [ ]) Moment of a magnet

**C [v]) Magnetic susceptibility**

D [ ]) Permittivity

19) Which of the following quantities consists of
SI unit as WATT ?

A [ ]) Force

B [ ]) Charge

C [ ]) Current

**D [v]) Power**

20) Rms value is defined based on which of the
following?

**A [v]) Heating effect**

B [ ]) Charge transfer

C [ ]) Current

D [ ]) Voltage

21) Which of the following defined the average
value ?

A [ ]) Voltage

B [ ]) Heating effect

C [ ]) Current

**D [v]) Charge transfer**

22) For symmetrical wave form average value of
one full cycle is

A [ ]) 1

B [ ]) 1.11

C [ ]) 2.22

**D [v]) 0**

23) If a pure inductor is connected across the ac
source, the average power taken by the

inductor is

A [ ]) A few watt

B [ ]) 100 watt

**C [v]) zero watt**

D [ ]) Maximum power

24) Average power taken by the pure capacitor is

**A [v]) Zero**

B [ ]) Minimum

C [ ]) Maximum

D [ ]) Any of the above

25) Which of the following is not a vector
quantity?

A [ ]) Linear momentum.

B [ ]) Angular momentum.

C [ ]) Electric field.

**D [v]) Electric potential.**

26) If conductance increases as temperature
increases it is called as ..........

**A [v]) Negative co-efficient**

B [ ]) Positive co-efficient

C [ ]) Both 1 & 2

D [ ]) None of the above

27) Which material has extremely large resistance
?

A [ ]) Semiconductor

B [ ]) Conductor

**C [v]) Insulator**

D [ ]) None of the above

28) What is mean by the rate of flow of an
electric charge ?

**A [v]) Electric current**

B [ ]) Electric potential

C [ ]) Electric resistance

D [ ]) None of the above

29) What is the unit of potential difference ?

A [ ]) Ohm

**B [v]) Volt**

C [ ]) Watt

D [ ]) Ampere

30) Which property is used to oppose the flow of
current ?

A [ ]) Poteintial difference

B [ ]) Capacitance

C [ ]) Inductance

**D [v]) Resistance**

31) What is the SI unit of electric current ?

**A [v]) Ampere**

B [ ]) Ohm

C [ ]) Faraday

D [ ]) None of the above

32) What is time period T?

A [ ]) Time taken by an alternating quantity to
complete the (+)ve half.

**B [v]) Time taken by an alternating quantity to complete the a cycle.**

C [ ]) Time taken by an alternating quantity to
complete the (-)ve half.

D [ ]) Time taken by an alternating quantity to
reach the peak value.

33) What is called the frequency in AC operation?

A [ ]) No. of (+)ve quadrature made per second.

**B [v]) No. of cycles made per second.**

C [ ]) No. of (-)ve quadrature made per second

D [ ]) No. of wave made per second.

34) What is the relation between time period T
and frequency?

**A [v]) T = 1 / frequency.**

B [ ]) T = 0.5 / frequency.

C [ ]) T = 0.85 / frequency.

D [ ]) T = frequency.

35) What is referred as the average value in AC
opearation?

A [ ]) Average of all values of an alternating
quantity.

B [ ]) Average of all values of the phase
sequences.

C [ ]) Average of all values of the (+)ve and
(-)ve half.

**D [v]) Average of all values of an alternating quantity over a complete cycle.**

36) What is form factor?

A [ ]) Average value / R.M.S. value

B [ ]) Average value / Peak value.

C [ ]) Instantaneous value / Average value.

**D [v]) R.M.S. value / Average value.**

37) Select the wave that has the least value of
form factor.

**A [v]) Square wave.**

B [ ]) Rectangular wave.

C [ ]) Triangular wave.

D [ ]) Sine wave.

38) What is the frequency of domestic power in
India?

**A [v]) 50 Hz.**

B [ ]) 60 Hz.

C [ ]) 220 Hz.

D [ ]) 70 Hz.

39) What is apparent power in AC operation?

A [ ]) Product of voltage and current.

**B [v]) Product of rms volatge and rms current.**

C [ ]) Product of voltage and current at no load.

D [ ]) Product of voltage and current at full
load.

40) What is the real power in AC operation?

A [ ]) VIcosφ.

B [ ]) Apperant power × cosφ.

**C [v]) Both option 1 & 2.**

D [ ]) None of these.

41) What is called the instantaneous value of an
alternating current?

**A [v]) The value of alternating quantity at any instant.**

B [ ]) The value of peak quantity at any instant.

C [ ]) The value of peak current at any instant.

D [ ]) The value of alternating frequency at any
instant.

42) What is called a cycle in case of AC
operation ?

A [ ]) When ac completes the (+)ve half, is
called a cycle.

**B [v]) When ac goes through a complete (+)ve to (-)ve, is called a cycle.**

C [ ]) When an alternating quantity completes the
(-)ve cycle, is called a cycle.

D [ ]) Option 1 and 2 both.

43) Capacitors for P.f correction are rated in

A [ ]) KW.

B [ ]) KVA.

C [ ]) KV.

**D [v]) KVAR.**

44) The field at any point on the axis of a
current carrying coil will be

A [ ]) parallel to axis.

B [ ]) perpendicular to the axis.

**C [v]) at angle of 45° with the axis.**

D [ ]) zero.

45) Two straight parallel conductors carry equal
currents in opposite direction. The force

between them is

**A [v]) repulsive.**

B [ ]) attractive.

C [ ]) zero.

D [ ]) none of above.

46) While comparing magnetic field and electric
circuits, the point of dissimilarity exists

while considering

A [ ]) mmf and emf.

B [ ]) reluctance and resistance.

**C [v]) flux and current flow.**

D [ ]) permeance and conductance.

47) Magnetism of a magnet can be destroyed by

A [ ]) hammering.

B [ ]) heating.

C [ ]) by inductive action of another magnet.

**D [v]) by all above methods.**

48) Ampere second is the unit of

A [ ]) conductance.

B [ ]) power

C [ ]) energy.

**D [v]) charge.**

49) If two point charges are denoted by + Q and -
Q and distance between this charges is

d, then the dipole moment P equal to

A [ ]) Q2 × d.

**B [v]) Q × d.**

C [ ]) Q / d2.

D [ ]) Q2 / d.

50) Electric flux in coulombs emanating from any
surface of a cube containing C coulombs

of charge at its centre i

A [ ]) Q / 4π.

B [ ]) 4πQ / 6E.

C [ ]) Q / 6.

**D [v]) Q / 6E.**

51) Electric displacement is a
____________________ quantity.

A [ ]) scalar.

**B [v]) vector.**

C [ ]) both of above.

D [ ]) none of above.

52) The unit of electric displacement vector is

**A [v]) C / m²**

B [ ]) Ampere-m.

C [ ]) C / m.

D [ ]) C - m.

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