Attempt Free Electrical Basic Questions 12 Here. Read The Important Electrical Basic Questions 12 MCQ From Below.
1) In half wave rectifiers, diode conducts during
a. Only positive half cycle
b. Only negative half cycle
c. Both positive and negative half cycle
d. Neither in positive half cycle nor in negative half cycle
ANSWER: Only positive half cycle
2) Specific resistance of a material is
a. Directly proportional to the both area of cross section and length of material
b. Directly proportional to the area of cross section and inversely proportional to the length of material
c. Inversely proportional to the area of cross section and directly proportional to the length of material
d. Inversely proportional to the both area of cross section and length of material
ANSWER: Directly proportional to the area of cross section and inversely proportional to the length of material
3) One coulomb of charge is equal to the charge of
a. 1.095 x 10 –19 electrons
b. 1.625 x 10–31 electrons
c. 6.242 x 1018 electrons
d. 6.025 x 10–19 electrons
ANSWER: 6.242 x 1018 electrons
4) Which among the following is true about ohm’s law?
a. I ∝ V
b. I = V/R
c. V = IR
d. All of these
ANSWER: All of these
5) In any network of wires carrying currents, the algebraic sum of all currents meeting at a point is equal to
a. Sum of all the currents
b. Zero
c. Sum of outgoing current
d. Sum of incoming current
ANSWER: Zero
Electrical Basic Questions 12
6) Electrical appliances which works on the electromagnetic principle is / are
a. Generators
b. Motors
c. Transformers
d. All of these
ANSWER: All of these
7) The materials with permeability less than unity are called
a. Diamagnetic materials
b. Paramagnetic materials
c. Ferromagnetic materials
d. Anti ferromagnetic materials
ANSWER: Diamagnetic materials
8) The magnetic materials which are strongly attracted by the magnet is
a. Diamagnetic materials
b. Paramagnetic materials
c. Ferromagnetic materials
d. Anti ferromagnetic materials
ANSWER: Diamagnetic materials
9) Permanent magnet are manufactured by
a. Copper sulphate
b. Iron and cobalt
c. Cobalt and nickel
d. ALNICO
ANSWER: ALNICO
10) The direction of magnetic materials when the current passes through the conductor is determined by
a. Right hand rule
b. Maxwell’s corkscrew rule
c. Left hand rule
d. Only (a) and (b)
ANSWER: Only (a) and (b)
Electrical Basic Questions 12
11) Coulomb’s First Law states that
a. Unlike poles attract each other
b. Like poles repel each other
c. Unlike poles attract each other and like poles repel each other
d. The force between two magnetic poles placed in a medium directly proportional to their pole strengths
ANSWER: Unlike poles attract each other and like poles repel each other
12) According to the couloumb’s second law, the force between two magnetic poles placed in a medium is
a. Directly proportional to their pole strengths.
b. Inversely proportional to the square of the distance between them
c. Inversely proportional to the absolute permeability of the surrounding medium
d. All of these
ANSWER: All of these
13) The unit of magnetic flux is
a. Maxwell
b. Weber
c. Weber – m
d. Only (a) and (b)
ANSWER: Only (a) and (b)
14) Reluctance in a magnetic material is a property by virtue of which it opposes the creation of
a. Electric flux
b. Magnetic flux
c. Electric field density
d. Electric lines of force
ANSWER: Magnetic flux
15) The unit of magnetizing field intensity is
a. Newton / Weber
b. Ampere – turns / Weber
c. Newton – m / Weber
d. Only (a) and (b)
ANSWER: Only (a) and (b)
Electrical Basic Questions 12
16) One electron charge is equal to
a. 1.925 x 10–31C
b. 1.6019 x 10-19C
c. – 1.925 x 10–31C
d. – 1.6019 x 10–19C
ANSWER: – 1.6019 x 10–19C
17) According to the coulomb’s law, the force between two point charges is
a. Directly proportional to the product of the charges
b. Inversely proportional to the square of the distance between them
c. Along the line joining them
d. All of these
ANSWER: All of these
18) Electric field intensity is
a. Directly proportional to the force applied
b. Inversely proportional to the force applied
c. Directly proportional to the permittivity
d. Inversely proportional to the charge
ANSWER: Directly proportional to the force applied
19) The equation for electric flux density is given by
a. D = εV
b. D = εE
c. D = ε/E
d. D = ε/V
ANSWER: D = εE
20) Electric flux density is a function of
a. Charge
b. Position
c. Medium
d. Only (a) and (b)
ANSWER: Only (a) and (b)
Electrical Basic Questions 12
21) The most common waveforms of ac is
a. Square
b. Triangular
c. Sinusoidal
d. Saw tooth
ANSWER: Sinusoidal
22) A radian is defined as the central angle, for which length of its arc
a. Should be greater than radius
b. Should be less than radius
c. Should be equal to the radius
d. None of these
ANSWER: Should be equal to the radius
23) Peak to peak value of a sine wave is
a. Equal to the maximum or phase value of sine wave
b. Twice the maximum or phase value of sine wave
c. Half of the maximum or phase value of sine wave
d. Four times the maximum or phase value of sine wave
ANSWER: Twice the maximum or phase value of sine wave
24) The number of instantaneous values between zero and the peak value is
a. Zero
b. One
c. Eleven
d. Infinity
ANSWER: Infinity
25) If the voltage increases from zero to peak value and decreases back to zero during one alteration, then the average value must bea. Less than zero
b. Greater than peak value
c. Between zero to peak value
d. None of these
ANSWER: Between zero to peak value
Electrical Basic Questions 12
26) In Fleming’s right hand rule, the direction of the induced emf in the conductor is given by
a. Index figure
b. Middle figure
c. Thumb
d. None of these
ANSWER: Middle figure
27) Yoke in a dc machine serves the function of
a. Providing mechanical support to the poles
b. Protects the dc machine from harmful atmospheric elements like dust, moisture and gases
c. Offers a path of low reluctances to the magnetic flux produced by the poles
d. All of these
ANSWER: All of these
28) Laminations or stampings are used to reduce the eddy current losses. The directionof laminations should be such that
a. They are perpendicular to the paths of eddy current and flux both
b. They are parallel to the paths of eddy current and flux both
c. They are perpendicular to the paths of eddy current and parallel to the flux
d. They are parallel to the path of eddy current and perpendicular to the flux
ANSWER: They are perpendicular to the paths of eddy current and parallel to the flux
29) The terminal voltage in the separately excited generators is given by
a. V = Eg – Ia Ra
b. V = Eg + Ia Ra
c. V = Eg – Ia Ra – If Ra
d. V = Eg + Ia Ra – If Ra
ANSWER: V = Eg – Ia Ra
30) In a self excited generator, if the series field opposes the shunt field, then the generator is
a. Cumulatively compounded
b. Differentially compounded
c. Series generator
d. None of these
ANSWER: Differentially compounded
Electrical Basic Questions 12
31) Tangent galvanometer can be used to measure
a. Voltage
b. Current
c. Power
d. All of these
ANSWER: Current
32) Wattmeter is a / an
a. Indicating instrument
b. Integrating instrument
c. Recording instrument
d. All of these
ANSWER: Indicating instrument
33) The magnetic effect is used in
a. Moving iron attraction type instrument
b. Moving iron repulsion type instrument
c. Electrostatic ammeters and voltmeters
d. All of these
ANSWER: All of these
34) The springs should be
a. Free from mechanical stress
b. They should have a small resistance
c. Sufficient cross-sectional area
d. All of these
ANSWER: All of these
35) In gravity control, at the zero position of the pointer the controlling torque is
a. Zero
b. One
c. 0.5
d. 7
ANSWER: Zero
36) Alternating voltage can be generated by
a. By rotating a coil in a magnetic field
b. By rotating a magnetic field within a stationary coil
c. Either (a) or (b)
d. Neither (a) or (b)
ANSWER: Either (a) or (b)
Electrical Basic Questions 12
37) The amplitude or peak value or maximum value of an alternating voltage is given by the coefficient of the
a. Sine of the time angle
b. Cosine of the time angle
c. Tangent of the time angle
d. Cotangent of the time angle
ANSWER: Sine of the time angle
38) Root mean square value of current is equal to
a. 1.414 times the maximum value
b. 1.732 times the maximum value
c. Twice the maximum value
d. 0.707 times the maximum value
ANSWER: 0.707 times the maximum value
39) The ratio of maximum value to effective value of an alternating quantity is called
a. Crest factor
b. Peak factor
c. Amplitude factor
d. All of these
ANSWER: All of these
40) The two alternating quantities could be added by constructing
a. Squares
b. Parallelograms
c. Rhombus
d. Trapeziums
ANSWER: Parallelograms
41) The undue deterioration in wiring due to the action of dampness, fumes, weather etc is
a. Appearance
b. Permanence
c. Mechanical immunity
d. Earthing
ANSWER: Permanence
Electrical Basic Questions 12
42) For a two – way position control of lamp, the number of switches required is
a. One
b. Two
c. Three
d. Four
ANSWER: Two
43) The voltage of the earthed appliance when it is higher and when it is lower than the earth potential will
a. Fall to zero, fall to zero
b. Fall to zero, increase to zero
c. Increase to zero, increase to zero
d. Increase to zero, fall to zero
ANSWER: Fall to zero, increase to zero
44) Necessity of earthing is to
a. Protect the human being from shock
b. Maintain the line voltage
c. Protect tall building
d. All of these
ANSWER: All of these
45) The most effective earth plate is
a. Copper plates
b. Cast – iron plates
c. Galvanized iron plates
d. All of these
ANSWER: Copper plates
46) Three – phase induction motor is more suitable than single – phase because
a. It is self starting
b. Better efficiency compared to single – phase
c. Better power factor compared to single – phase
d. All of these
ANSWER: All of these
Electrical Basic Questions 12
47) Commutator motors have
a. Absolutely uniform torque
b. Approximately uniform torque
c. Non – uniform torque
d. None of these
ANSWER: Non – uniform torque
48) When windings of 3 – phase induction motor is rotated in a magnetic field, then the emf induced in each phase are of
a. Same magnitude but different frequency
b. Different magnitude but same frequency
c. Same magnitude and same frequency
d. Different magnitude and different frequency
ANSWER: Same magnitude and same frequency
49) In a 3 – phase star connected balanced induction motor, the line voltage is equal to the
a. 3 times the phase voltage
b. √3 times the phase voltage
c. 1/√3 times the phase voltage
d. 1/3 times the phase voltage
ANSWER: √3 times the phase voltage
50) In a star connected system, the current flowing through the line is
a. Greater than the phase current
b. Equal to the phase current
c. Lesser than the phase current
d. None of these
