Explore topic-wise MCQs in Electrical Engineering Questions.

This section includes 715 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.

51.

Why is A.C.S.R conductor used as the replacement or substitute for copper?
A. Higher current carrying capacity.
B. Economy.
C. Being less weight.
D. Higher tensile strength.
Answer» C. Being less weight.
Discussion
52.

A 132 kV transmission line, with the weight of conductor = 680 kg/km, length of span = 260 m, ultimate strength = 3100 kg, safety factor =2. Calculate the height above ground at which the conductor should be supported. Ground clearance required is 10 m.
A. 10.7 m
B. 13.7 m
C. 20.83 m
D. 18.75 m
Answer» C. 20.83 m
Discussion
53.

Conductor sag should be kept
A. Minimum
B. Maximum
C. Zero
D. None of these
Answer» B. Maximum
Discussion
54.

What is the shape that is attained by the conductors if suspended from the same height?
A. Parabola
B. Catenary
C. Semi circle
D. None of these
Answer» C. Semi circle
Discussion
55.

Sag is directly proportional to the square of span.
A. True
B. False
Answer» B. False
Discussion
56.

What is the function of steel wire in A.C.S.R conductors?
A. Compensate for skin effect.
B. Takes care of surges.
C. Reduced capacitance and inductance.
D. Provide additional mechanical strength.
Answer» E.
Discussion
57.

Assertion (A): The maximum operating temperature of overhead line conductors made of aluminium or copper is restricted to 75 °C. Reason (R): conductors beyond this limit may shatter the insulator.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the explanation of A
C. A is true but R is false
D. A is false but R is true.
Answer» D. A is false but R is true.
Discussion
58.

What is the general ratio of the cross sectional area of the two metals used in the A.C.S.R conductors?
A. 1 : 8
B. 1 : 4
C. 4 : 3
D. 2 : 1
Answer» C. 4 : 3
Discussion
59.

Why is grease added between steel and aluminium conductors?
A. To reduce the corrosion by electrolytic action.
B. To reduce friction between the strand.
C. To eliminate the air gaps.
D. To reduce the leakage of current.
Answer» B. To reduce friction between the strand.
Discussion
60.

What is the minimum horizontal clearance of a LV line from a residential building?
A. 0.6 m.
B. 0.9 m.
C. 1.2 m.
D. 1.6 m.
Answer» D. 1.6 m.
Discussion
61.

In India, which types of poles are commonly used for distribution?
A. Wooden poles
B. RCC poles
C. Steel poles
D. Both (b) and (c)
E. None of these
Answer» E. None of these
Discussion
62.

For high voltage transmission lines, why are conductors suspended from towers?
A. Increase the clearance from ground.
B. Reduce clearance from ground.
C. Take care of increase in length.
D. Reduce the environmental effects.
Answer» B. Reduce clearance from ground.
Discussion
63.

Which among these are the properties for the line supports?
A. Higher mechanical strength
B. Light in weight
C. Easy accessibility of conductors for maintenance
D. All of these
Answer» E.
Discussion
64.

What are the different types of vibrations in the vertical plane?
A. Aeoline vibrations
B. Galloping
C. Both (a) and (b)
D. None of these
Answer» D. None of these
Discussion
65.

What is the line length if a load of 15000 kW at a power factor 0.8 lagging can be delivered by a 3 phase transmission line having conductors each of resistance 1 Ω per kilometre? The voltage at the receiving end is to be 132kV and the loss is about 5%.
A. 40.13km
B. 37.18km
C. 42.38km
D. 35.87km
Answer» C. 42.38km
Discussion
66.

What is the total charging current per phase for a 33 kV, 50 Hz, 3 phase underground cable of 4 km length using 3 single core cables? Each conductor has a diameter of 2.5 cm and the radial thickness of insulation is 0.5 cm.
A. 15.28 A
B. 11.87 A
C. 13.85 A
D. 8.25 A
Answer» C. 13.85 A
Discussion
67.

On which factor does the capacitance of the cable depend?
A. Length of cable
B. Relative permittivity of dielectric used in cable
C. Ratio of sheath diameter and core diameter
D. All of the above
Answer» E.
Discussion
68.

Why the belted type cable constructions are not suitable for voltages exceeding 22 kV?
A. Development of both radial and tangential stress
B. Formation of vacuous spaces and voids on loading and unloading owing to non homogeneity of dielectric in belted construction
C. Local heating caused by power loss at the centre filling
D. All of the above
Answer» E.
Discussion
69.

The cable best suited for the transmission of voltages from 33 kV to 66 kV is_______________.
A. Belted cables
B. Screened cables
C. Pressure cables
D. None of these
Answer» C. Pressure cables
Discussion
70.

What is / are the advantages of using H-type cables?
A. The metallic screens assist in complete impregnation of the cable with the compound
B. The metallic screens increase the heat dissipating power of the cable
C. The lead sheaths in H type are thicker then S.L type cables
D. All of these
Answer» E.
Discussion
71.

Why are the ternary lead cables used near the railway tracks?
A. Because they have high tensile strength
B. Have a low coefficient of thermal expansion
C. Have low specific gravity
D. Can withstand shocks and vibrations
Answer» D. Can withstand shocks and vibrations
Discussion
72.

What is the advantage(s) of screened type over the belted cables?
A. Reduced possibility of core to core faults
B. Increased current carrying capacity
C. No possibility of formation of voids within the dielectric
D. All of the above
Answer» E.
Discussion
73.

Why solid type of conductors is not preferred for the voltages exceeding 66 kV?
A. A danger of breakdown of insulation
B. Skin effect dominates the conductor
C. There is corona loss between conductor and sheath material
D. Insulation melts due to overheating
Answer» B. Skin effect dominates the conductor
Discussion
74.

The most ideal material for the over head conductor is copper. What are the advantages of this?
A. Smaller cross sectional area.
B. Area offered by the wind loads is reduced.
C. The price of copper is less.
D. Both (a) and (b).
E. None of these
Answer» E. None of these
Discussion
75.

The charging current drawn by the cable _____________.
A. Lags behind the voltage by 90°
B. Leads the voltage by 90°
C. Are in phase with each other
D. Leads the voltage by 60°
Answer» C. Are in phase with each other
Discussion
76.

What is the effect of temperature rise on the over head lines?
A. Increase the sag and decrease the tension
B. Decrease the sag and increase the tension
C. Both increases
D. Both decreases
Answer» B. Decrease the sag and increase the tension
Discussion
77.

A single core cable has a conductor diameter of 1 cm and the internal sheath diameter of 1.8 cm. If impregnated paper of relative permittivity 4 is used as the insulation, calculate the capacitance for 1 km length of cable?
A. 0.378 μ F
B. 0.257 μ F
C. 0.549 μ F
D. 0.78 μ F
Answer» B. 0.257 μ F
Discussion
78.

Which among these is not the component of over head transmission lines?
A. Conductors
B. Cross arms
C. Danger plates
D. Transformers
Answer» E.
Discussion
79.

Which among these properties are not suitable for the conductor material?
A. High electrical conductivity.
B. High specific gravity.
C. Lower cost.
D. High tensile strength.
Answer» C. Lower cost.
Discussion
80.

What is the empirical formula to calculate the number of strands?
A. 3n (n+2n) + 2
B. 3n (n+1) + 2
C. 3n (n+1) + 1
D. 3n (3+ 3n) + 1
Answer» D. 3n (3+ 3n) + 1
Discussion
81.

Which among the following properties has got a higher value for aluminium in comparison to that of copper?
A. Electrical resistivity.
B. Melting point.
C. Thermal conductivity.
D. Specific gravity.
Answer» B. Melting point.
Discussion
82.

Why are galvanised steel conductors not suitable for transmitting large power over long distance?
A. Poor conductivity.
B. High resistance of steel.
C. More power loss.
D. Both (a) and (b).
E. None of these
Answer» E. None of these
Discussion
83.

Why are the conductors used for higher voltage transmission stranded?
A. Ease of handling.
B. Cheaper cost.
C. Reduced resistivity.
D. Increase in tensile strength.
Answer» B. Cheaper cost.
Discussion
84.

Hot template curves are a plot between
A. Temperature and humidity
B. Conductors sag and span lengths
C. Conductor weight and sag
D. None of these
Answer» C. Conductor weight and sag
Discussion
85.

The following materials of line conductor are given. i. Hard drawn copper. ii. Cadmium copper. iii. Aluminium. iv. Galvanised steel. What is the correct series in descending order of their electrical conductivities?
A. i, ii, iv, iii.
B. ii, i, iv, iii.
C. ii, i, iii, iv.
D. i, ii, iii, iv.
Answer» E.
Discussion
86.

Which material is used for the manufacture of ground wire?
A. Aluminium
B. Galvanised steel
C. Cast iron
D. Stainless steel
Answer» C. Cast iron
Discussion
87.

Safety factor is the ratio of
A. Working stress to breaking stress.
B. Breaking stress to working stress.
C. 1 / breaking stress.
D. 1 / working stress.
Answer» C. 1 / breaking stress.
Discussion
88.

The maximum tension in a section of overhead line conductor between two supports of unequal height occurs at
A. The higher support
B. The lower support
C. Midpoint of the conductors
D. None of these
Answer» B. The lower support
Discussion
89.

Why is stringing chart useful?
A. For finding the sag in the conductor
B. In the design of insulator string
C. In the design of tower
D. To find the distance between the towers
Answer» B. In the design of insulator string
Discussion
90.

What is the minimum clearance of HV lines from ground across the streets?
A. 3 m.
B. 6 m.
C. 5 m.
D. 8 m.
Answer» C. 5 m.
Discussion
91.

Galloping in transmission line conductors arises due to
A. Asymmetrical layers of ice formation.
B. Vortex phenomenon in light winds.
C. Heavy weight of the line conductors.
D. Adoption of horizontal conductor configuration.
Answer» B. Vortex phenomenon in light winds.
Discussion
92.

If a 132 kV line passes over a residential building, what shall be the minimum vertical clearance from the roof of the building?
A. 3 m.
B. 4.57 m.
C. 6.38 m.
D. 9.27 m.
Answer» C. 6.38 m.
Discussion
93.

Why is the single core cables not provided with armouring?
A. Avoids excessive loss in the armour
B. Make the cable more flexible
C. Make the cable non hygroscopic
D. None of the above
Answer» B. Make the cable more flexible
Discussion
94.

How many cores are used in a cable for the transmission of voltages upto 66 kV?
A. Single core
B. Two core
C. Three core
D. All of the above
Answer» D. All of the above
Discussion
95.

Higher the frequency, _____________.
A. Lower the corona loss
B. Higher is the corona loss
C. Does not effect
D. Depends on the physical conditions
Answer» C. Does not effect
Discussion
96.

What is the percentage of added materials like sulphur, zinc lead etc in vulcanised rubber?
A. 5 – 10 %
B. 3 – 5 %
C. 4 – 8 %
D. 10 – 12 %
Answer» C. 4 – 8 %
Discussion
97.

What is empire tape?
A. Impregnated paper
B. Vulcanised rubber
C. Enamel insulation
D. Varnished cambric
Answer» E.
Discussion
98.

On which factor is the corona loss dependent?
A. Material of the conductor
B. Diameter of the conductor
C. Height of the conductor
D. None of these
Answer» C. Height of the conductor
Discussion
99.

What is the dielectric strength of impregnated paper?
A. 30 kV/mm
B. 20 kV/mm
C. 15 kV/mm
D. 5 kV/mm
Answer» B. 20 kV/mm
Discussion
100.

The thickness of insulation provided on the conductor in the cable depends on which among the following factor?
A. Operating voltage
B. Current to be carried
C. Power factor
D. Both (a) and (b)
Answer» B. Current to be carried
Discussion