Explore topic-wise MCQs in Electrical Engineering.

This section includes 33 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.

1.

Which of the following could be lamina-proximately the thickness of laminations of a D.C. machine ?

A. 0.005 mm
B. 0.05 mm
C. 0.5 m
D. 5 m
Answer» D. 5 m
Discussion
2.

While applying Fleming's right-hand rule to And the direction of induced e.m.f., the thumb points towards

A. direction of induced e.m.f.
B. direction of flux
C. direction of motion of the conductor if forefinger points in the direction of generated e.m.f.
D. direction of motion of conductor, if forefinger points along the lines of flux
Answer» E.
Discussion
3.

For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f. ?

A. Lap winding
B. Wave winding
C. Either of (a) and (b) above
D. Depends on other features of design
Answer» C. Either of (a) and (b) above
Discussion
4.

In D.C. generators, the brushes on commutator remain in contact with conductors which

A. lie under south pole
B. lie under north pole
C. lie under interpolar region
D. are farthest from the poles
Answer» D. are farthest from the poles
Discussion
5.

If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be

A. demagnetisation only
B. cross magnetisation as well as magnetisation
C. crossmagnetisation as well as demagnetising
D. cross magnetisation only
Answer» D. cross magnetisation only
Discussion
6.

If a cable of homogeneous insulation has a maximum stress of 10 kV/mm, then the dielectric strength of insulation should be

A. 5 kV/mm
B. 10 kV/mm
C. 15 kV/mm
D. 30 kV/mm
Answer» C. 15 kV/mm
Discussion
7.

The terminal voltage of a series generator is 150 V when the load current is 5 A. If the load current is increased to 10 A, the terminal voltage will be

A. 150 V
B. less than 150 V
C. greater than 150 V
D. none of the above
Answer» D. none of the above
Discussion
8.

The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage

A. will be less than 250 V
B. will always be 250 V
C. may be greater or less than 250 V
D. none of the above
Answer» D. none of the above
Discussion
9.

The number of armature parallel paths in a two-pole D.C. generator having duplex lap winding is

A. 2
B. 4
C. 6
D. 8
Answer» C. 6
Discussion
10.

The main factor which leads to unstable parallel operation of flat and over compounded generators is

A. their rising voltage characteristics
B. unequal number of turns in their series field windings
C. unequal speed regulation of their primemovers
D. unequal series field resistances
Answer» B. unequal number of turns in their series field windings
Discussion
11.

As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately

A. 40 percent
B. 25 percent
C. 10 percent
D. 5 percent
Answer» E.
Discussion
12.

If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to

A. reverse the field connections
B. increase the field resistance
C. increase the speed of primemover
D. check armature insulation resis tance
Answer» B. increase the field resistance
Discussion
13.

If a power cable and a communication cable are to run parallel the minimum distance between the two, to avoid interference, should be

A. 2 cm
B. 10 cm
C. 50 cm
D. 400 cm
Answer» D. 400 cm
Discussion
14.

In congested areas where excavation is expensive and inconvenient 'draw in system' of laying of underground cables is often adopted.

A. Yes
B. No
C. none
D. none
Answer» B. No
Discussion
15.

In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilised is called

A. rotor
B. stator
C. field
D. armature
Answer» E.
Discussion
16.

In a D.C. generator in case the resistance of the field winding is increased, then output voltage will

A. increase
B. decrease
C. remain unaffected
D. fluctuate heavily
Answer» C. remain unaffected
Discussion
17.

Which of the following D.C. generators will be in a position to build up without any residual magnetism in the poles ?

A. Series generator
B. Shunt generator
C. Compound generator
D. None of the above
Answer» E.
Discussion
18.

Which of the following generator will have negligible terminal voltage while running on no-load ?

A. Series generator
B. Shunt generator
C. Compound generator
D. Separately excited generator
Answer» B. Shunt generator
Discussion
19.

The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except

A. armature reaction
B. armature resistance drop
C. field weakening due to armature reaction and armature
D. commutation
Answer» E.
Discussion
20.

A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave

A. will be zero
B. will be of 5 Hz
C. willbeof5xiVHz
D. will be of v Hz 5
Answer» C. willbeof5xiVHz
Discussion
21.

A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be

A. zero
B. about 2 V
C. about 50 V
D. 220 V
Answer» C. about 50 V
Discussion
22.

If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be

A. zero
B. small
C. the same as rated voltage
D. high
Answer» B. small
Discussion
23.

Which of the following generators will be preferred if they are required to be run in parallel ?

A. Shunt generators
B. Series generators
C. Compound generators
D. None of the above
Answer» B. Series generators
Discussion
24.

Two generators are running in parallel. One of the generators may run as motor for which of the following reasons ?

A. The direction of that generator is reversed
B. The speed of that generator is increased
C. The field of that generator is weakened
D. That generator takes large share of loads
Answer» E.
Discussion
25.

D.C. generators are connected to the busbars or disconnected from them only under the floating condition

A. to avoid sudden loading of the primemover
B. to avoid mechanicaljerk to the shaft
C. to avoid burning of switch contacts
D. all above
Answer» E.
Discussion
26.

In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when

A. r.p.m. is more than 300
B. r.p.m. is less than 300
C. number of poles is 4
D. number of poles is 2
Answer» E.
Discussion
27.

In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralised by all of the following except

A. interpoles
B. dummy coils
C. compensating winding
D. shifting of axis of brushes
Answer» C. compensating winding
Discussion
28.

A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly

A. 150 V
B. 175 V
C. 240 V
D. 290 V
Answer» D. 290 V
Discussion
29.

To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them

A. just ahead of magnetic neutral axis
B. in magnetic neutral axis
C. just behind the magnetic neutral axis
Answer» B. in magnetic neutral axis
Discussion
30.

Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator ?

A. Dummy coils
B. Commutator
C. Eye bolt
D. Equilizer rings
Answer» C. Eye bolt
Discussion
31.

If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by

A. Blv
B. Blv2
C. Bl2v
D. Bl2v2
Answer» B. Blv2
Discussion
32.

In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be

A. 4
B. 8
C. 16
D. 32
Answer» C. 16
Discussion
33.

A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be_____________?

A. zero
B. about 2 V
C. about 50 V
D. 220 V
Answer» C. about 50 V
Discussion