Results for electrical engineering

Basic Electrical Engineering MCQ-14

August 15, 2019

Basic Electrical Engineering MCQ-14




41. Which of the following statement about D.C. generators is false ?
(a) Compensating winding in a D.C. machine helps in commutation
(b) In a D. C. generator interpoles winding is connected in series with the armature
winding
(c) Back pitch and front pitch are both odd and approximately equal to the pole pitch
(d) Equilizing bus bars are used with parallel running of D.C. shunt generators
Ans: d
42. The demagnetising component of armature reaction in a D.C. generator
(a) reduces generator e.m.f.
(b) increases armature speed
(c) reduces interpoles flux density
(d) results in sparking trouble
Ans: a
43. Magnetic field in a D.C. generator is produced by
(a) electromagnets
(b) permanent magnets
(c) both (a) and (b)
(d) none of the above
Ans: a
44. The number of brushes in a commutator depends on
(a) speed of armature
(b) type of winding
(c) voltage
(d) amount of current to be collected
Ans: d
45. Compensating windings are used in D.C. generators
(a) mainly to reduce the eddy currents by providing local short-circuits
(b) to provide path for the circulation of cooling air
(c) to neutralise the cross-magnetising effect of the armature reaction
(d) none of the above
Ans: c
46. 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
Ans: b
47. In a D.C. generator the ripples in the direct e.m.f. generated are reduced by
(a) using conductor of annealed copper
(b) using commutator with large number of segments
(c) using carbon brushes of superior quality
(d) using equiliser rings
Ans: c

48. In D.C. generators, lap winding is used for
(a) high voltage, high current
(b) low voltage, high current
(c) high voltage, low current
(d) low voltage, low current
Ans: b
49. Two generators A and B have 6-poles each. Generator A has wave wound armature
while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A
and B will be
(a)    2 : 3
(b) 3 : 1
(c) 3 : 2
(d) 1 : 3
Ans: b
50. The voltage drop for which of the following types of brush can be expected to be least ?
(a) Graphite brushes
(b) Carbon brushes
(c) Metal graphite brushes
(d) None of the above
Ans: c
Basic Electrical Engineering MCQ-14 Basic Electrical Engineering MCQ-14 Reviewed by Sikha on August 15, 2019 Rating: 5

Basic Electrical Engineering MCQ- 13

August 15, 2019


Basic Electrical Engineering MCQ- 13


31. 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
Ans: d
32. Eddy currents are induced in the pole shoes of a D.C. machine due to
(a) oscillating magnetic field
(b) pulsating magnetic flux
(c) relative rotation between field and armature
(d) all above
Ans: c
33. In a D.C. machine, short-circuited field coil will result in
(a) odour of barning insulation
(b) unbalanced magnetic pull producing vibrations
(c) reduction of generated voltage for which excitation has to be increased to maintain the
voltage
(d) all above
Ans:
34. Equilizer rings are required in case armature is
(a) wave wound
(b) lap wound
(c) delta wound
(d) duplex wound
Ans: b
35. Welding generator will have
(a) lap winding
(b) wave winding
(c) delta winding
(d) duplex wave winding
Ans: a
36. In case of D.C. machine winding, number of commutator segments is equal to
(a) number of armature coils
(b) number of armature coil sides
(c) number of armature conductors
(d) number of armature turns
Ans: a
37. For a D.C. machines laboratory following type of D.C. supply will be suitable
(a) rotary converter
(b) mercury are rectifier
(c) induction motor D.C. generator set
(d) synchronous motor D.C. generator set
Ans: c
38. The function of pole shoes in the case of D.C. machine is
(a) to reduce the reluctance of the magnetic path
(b) to spread out the flux to achieve uniform flux density
(c) to support the field coil
(d) to discharge all the above functions
Ans: d
39. In the case of lap winding resultant pitch is
(a) multiplication of front and back pitches
(b) division of front pitch by back pitch
(c) sum of front and back pitches
(d) difference of front and back pitches
Ans: d
40. A D.C. welding generator has
(a) lap winding
(b) wave moving
(c) duplex winding
(d) any of the above
Ans: a
Basic Electrical Engineering MCQ- 13 Basic Electrical Engineering MCQ- 13 Reviewed by Sikha on August 15, 2019 Rating: 5

Basic Electrical Engineering MCQ- 12

August 15, 2019

Basic Electrical Engineering MCQ- 12
21. In D.C. generators, current to the external circuit from armature is given through
(a) commutator
(b) solid connection
(c) slip rings
(d) none of above
Ans: a
23. Brushes of D.C. machines are made of
(a) carbon
(b) soft copper
(c) hard copper
(d) all of above
Ans: a

24. 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
Ans: a
25. 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
Ans: b

26. The material for commutator brushes is generally
(a) mica
(b) copper
(c) cast iron
(d) carbon
Ans: d
27. The insulating material used between the commutator segments is normally
(a) graphite
(b) paper
(c) mica
(d) insulating varnish
Ans: c
28. 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
Ans: c
29. 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
Ans: c

30. Armature reaction of an unsaturated D.C. machine is
(a) crossmagnetising
(b) demagnetising
(c) magnetising
(d) none of above
Ans: a

Basic Electrical Engineering MCQ- 12 Basic Electrical Engineering MCQ- 12 Reviewed by Sikha on August 15, 2019 Rating: 5

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 4

June 22, 2019

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 4

A short circuit is that which 



(a) uses short pieces of wire 
(b) goes only a short distance
(c) is used for dimming light 
(d) offers very low resistance path for current to flow

Which of the following stays the same in all parts of a series circuit? 

(a) Voltage 
(b) power
(c) resistance
(d) current


 The resistance of the windings of a generator is known as 

(a) generated resistance
 (b) field resistance
(c) internal resistance
 (d) terminal resistance

 Ohm‟s law is applicable to 


(a) Semi-conductors 
(b) vacuum tubes
(c) electrolytes 
(d) none of these



A wire of length l of a circular cross-section of radius r has a resistance of R ohms. Another wire of same material and a cross-sectional radius 2r will have the same resistance R if the length is 



(a) 2l 
(b) l/2
(c) 4l 
(d) l2



 With the rise in temperature, the temperature coefficient of resistance 


(a) remains unaffected 
(b) increases
(c) decreases 
(d) uncertain



The values of the temperature coefficient of resistance of a given conductor are‟ 


(a) the same at different temperatures 
(b) higher at higher temperatures
(c) different at different temperatures 
(d) none of the above



 Temperature coefficient of resistance is defined as 


(a)increase in resistance per ohm per °C
 (b) increase in resistance per °C
(c) decrease in resistance per ohm per °C
(d) the ratio of decrease in resistance per °C to the resistance at 0°C



 The resistance of a parallel circuit consisting of two resistors is 12Ω. One of the resistance wires breaks and the effective resistance becomes 18Ω. The resistance of the broken wire is 




(a) 48 Ω

 (b) 18 Ω
(c) 36 Ω
 (d) 24 Ω


When one leg of a parallel circuit gets opened out, the current drawn from the supply will


(a)reduce 
(b) increase 

(c) remain the same 
(d) uncertain



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Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 4 Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 4 Reviewed by Sikha on June 22, 2019 Rating: 5

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 3

June 22, 2019

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 3
Which of the following relation is incorrect 
(a) P = VI
 (b) P=I2R
(c) P= V∕R2
(d) P= V2∕R
 If I, R and t are the current, resistance and time respectively, then according to Joule‟s law heat produced will be proportional to 
(a) I2Rt 
(b) I2Rt2
(c) I2R2t 
(d) I2R2t2

 When a low resistance is connected in parallel with a high resistance, the combined
resistance is ( B )

 (a) always more than the high resistance 
(b) always less than the low resistance
(c) always between the value of high and low resistance
(d) either lower or higher than low resistance depending on the value of high resistance

 Two 100 W, 200 V lamps are connected in series across a 200 V supply. The total power consumed by each lamp will be watts. ( A )
(a)25 
(b) 50
(c) 100 
(d) 200
The factor which will have least effect on the voltage at the load end of a two-wire supply circuit is ( B )

 (a) length of the circuit 
(b) whether supply frequency is 25 Hz or 50 Hz
(c) amount of load on the circuit 
(d) cross section of the current wires
For a given line voltage, four heating coils will produce maximum heat when connected
(a)all in parallel 
(b) all in series 
(c) with two parallel pairs in series 
(d) on pair in parallel with the other two in series
For current to flow, a circuit must be ( C )
(a) Isolated 
(b) insulated
(c) complete 
(d) protected
If a live‟ conductor of a public supply touches earth metal ( D )

 (a) supply voltage will increase 
(b) supply voltage will decrease
(c) no current will flow 
(d) current will flow to earth
The material used for fuse must have 
(a) Low melting point and low specific resistance
(b) Low melting point and high specific resistance
(c) High melting point and low specific resistance

  Which of the following statements regarding a capacitor is not true? 
(a) dc cannot flow through it (b) ac can flow through‟ it
(c) current flows when a capacitor is connected for the first time across a battery

(d) slight moisture increases its capacitance
Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 3 Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 3 Reviewed by Sikha on June 22, 2019 Rating: 5

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 2

June 22, 2019

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 2



The resistance of a parallel circuit consisting of two branches is 12 ohms. If the resistance of one branch is 18 ohms, what is the resistance of the other ? 

(a) 18 Ω (b) 36 Ω
(c) 48 Ω (d) 64 Ω

Ans :( B )


 Four wires if same material, the same cross-sectional area and the same length when connected in parallel give a resistance of 0.25 Ω. If the same four wires are connected is series the effective resistance will be 
(a) 1 Ω (b) 2 Ω
(c) 3 Ω (d) 4 Ω

Ans :( D)

 Which of the following materials has a negative temperature co-efficient of resistance?
(a) Copper (b) Aluminum
(c) Carbon (d) Brass 

Ans :( C )

 Which of the following statement is true? 
(a) A galvanometer with low resistance in parallel is a voltmeter
(b) A galvanometer with high resistance in parallel is a voltmeter
(c)A galvanometer with low resistance in series is an ammeter
(d) A galvanometer with high resistance in series is an ammeter

Ans: ( C )

 A closed switch has a resistance of 
(a) Zero (b) about 50 ohms
(c) about 500 ohms (d) infinity


Ans: ( A )


The thickness of insulation provided on the conductor depends on 
(a)The magnitude of voltage on the conductor
(b)The magnitude of current flowing through it
(c) Both (a) and (b)
(d) None of the above

Ans: ( A )


Which of the following quantities remain the same in all parts of a series circuit? 
(a) Voltage (b) Current
(c) Power (d) Resistance

Ans: ( B )


 In an electric kettle water boils in 10 minutes. It is required to boil the boiler in 15 minutes, using same supply mains 


(a) Length of heating element should be decreased
(b) Length o heating element should be increased
(c) Length of heating element has no effect on heating if water
(d) None of the above

Ans: ( A )

 Bulbs in street lighting are all connected in 

(a) Parallel (b) series
(c) series-parallel (d) end-to-end


Ans: ( A )


Sparking occurs when a load is switched off because the circuit has high 
(a) Resistance (b) inductance
(c) capacitance (d) impedance


Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 2 Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics set 2 Reviewed by Sikha on June 22, 2019 Rating: 5

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics

June 22, 2019

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics


 One commercial unit of energy equals 
(a) 500 watt-seconds 
(b) one watt-hour
(c)One kilowatt-hour
 (d) ten kilowatt-hour
The electrical energy required to heat a bucket of water to a certain temperature is 4 kWh. If the heat losses are 20 percent, the energy input is 
(a) 2 kWh 
(b) 3.2 kWh
(c) 5 k Wh 
(d) 6 k Wh
3. The maximum current rating for a 10kΩ, 0.5 W resistor is 
(a) 0.707 mA 
(b) 7.07 mA
(c) 14.14 mA 
(d) 28.28 mA
The substances which have a large number of free electrons and offer a low resistance
are called 
(a) Insulators (b) inductors
(c)Semi-conductors (d) conductors
The resistance of a conductor varies inversely as 
(a) length 
(b) area of cross-section
(c) temperature 
(d) resistivity
With rise in temperature the resistance of pure metals 
(a) Increases 
(b) decreases
(c) first increases and then decreases
 (d) remains constant

The resistance of a copper wire 200 m long is 21Ω. If its thickness (diameter) is 0.44 mm, its specific resistance is around 
(a) 1.2 x 10-8Ω-m 
(b) 1.4 x 10-8Ω-m
(c) 1.6 x 10-8Ω-m 
(d) 1.8 x 10-8Ω-m

 Three resistances of 10 ohms, 15 ohms and 30 ohms are connected in parallel. The total resistance of the combination is 
(a)5 ohms
(b) 10 ohms
(c)15 ohms 
(d) 55 ohms
9. The resistance of two wires is 25 Ω when connected in series and 6 Ω when joined in parallel. The resistance of each wire is 
(a)10 Ω, 15 Ω 
(b) 20 Ω, 30 Ω
(c) 5 Ω, 10 Ω 
(d) 10 Ω, 20 Ω

 10. An instrument which detects electric current is known as 
(a) Voltmeter 
(b) rheostat
(c) wattmeter 
(d) galvanometer

Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics Electrical Engineering MCQ|Objective questions Electrical Engineering|Industries Extension officer|Lecturer in Polytechnics Reviewed by Sikha on June 22, 2019 Rating: 5

Basic Electrical MCQ set 1

February 26, 2019

Basic Electrical MCQ set 1



Transformers




1. A transformer works on the principle of

A. Faraday's law of electrolysis
B. Mutual induction between two inductively coupled circuits..
C. Self induction of coils
D. Conduction of current between primary and secondary

2. When a DC supply is given at primary of an unloaded transformer

A. Primary will carry heavy current and may possibly burn..
B. Secondary will carry heavy current
C. We will get high voltage on secondary side
D. We will get a A.C voltage on the secondary side according to run ratio

3. Buchholz relay is used in

A. line protection
B. Motor protection
C. Generator Protection
D. Transformer protection..

4. The temperay
Basic Electrical MCQ set 1 Basic Electrical MCQ set 1 Reviewed by Sikha on February 26, 2019 Rating: 5

Basic Electrical Engineering MCQ's set 3 for Industrial Extension Officer,RRB JE, SSC JE,Sub Engineer Electrical, Line Man, Electrician

January 05, 2019



Basic Electrical Engineering set 3
Hi friends, in this post, I would like to discuss with you some objective questions on Basic Electrical Engineering. This will be helpful for RRB JE, SSC JE, Industrial Extension officer Kerala PSC,Sub Engineer Electrical, Line Man, Electrician etc.




1.     If three, 30 µF capacitance are connected in series. Find  the effective value

·        30 µF

·        60 µF

·        90 µF

·        10 µF….

2.     A thermistor has

·        High temperature co-efficient

·        Variable temperature co-efficient

·        Positive temperature co-efficient

·        Negative temperature co-efficient…

3.     One horse power is

·        735.5 Nm/s….

·        756 watts

·        1000 Wh

·        745 Ws

4.     The unit of inductance is

·        Webbber

·        Farad

·        Semens

·        Hentry…

5.     Unit of conductance is

·        Seimen….

·        Ohm

·        Tesla

·        Weber

6.     An electric lamp of 40 watt will consume one unit of energy in ………. Hours

·        2.5

·        4

·        25…..

·        40

7.      The” super position theorem” is essentially based on the concept of

·        Duality

·        Linearity….

·        Reciprocity

·        Non-linearity

8.     Solder is an alloy of

·        Lead-tin……

·        Copper- tin

·        Tin -silver

·        Tin –silver- lead

9.     A closed switch has a resistance of

·        Zero….

·        Infinity

·        About 10ohm

·        Atleast 1 k ohm

10.                        Which device stores electrical energy?

·        Inductor

·        Capacitor……

·        Thermistor

·        Resistor
Basic Electrical Engineering MCQ's set 3 for Industrial Extension Officer,RRB JE, SSC JE,Sub Engineer Electrical, Line Man, Electrician Basic Electrical Engineering MCQ's set 3 for Industrial Extension Officer,RRB JE, SSC JE,Sub Engineer Electrical, Line Man, Electrician Reviewed by Sikha on January 05, 2019 Rating: 5

MCQ s on Basic Electrical Engineering set 2 for Industrial Extension Officer,RRB JE, SSC JE,Sub Engineer Electrical, Line Man, Electrician

January 04, 2019

Basic Electrical Engineering set 2
Hi friends, in this post, I would like to discuss with you some objective questions on Basic Electrical Engineering. This will be helpful for RRB JE, SSC JE, Industrial Extension officer Kerala PSC,Sub Engineer Electrical, Line Man, Electrician etc.

1.     Which device stores electrical energy?

·        Inductor

·        Capacitor……

·        Thermistor

·        Resistor

2.     What is the unit of conductance?

·        Ohm

·        Mho….

·        Henry

·        Watt

3.     Heat developed in conductor is proportional to the square of the:

·        Current….

·        Voltage

·        Power

·        Time

4.     From the following materials, which one has higher resistivity at 200 C:

·        Copper

·        German silver

·        Mercury

·        Nichrome….

5.     The resistance of a heating coil required in a 2500 watts heater used on 200 V main will be

·        10.25 ohms

·        16 ohms….

·        25 ohms

·        12.5 ohms

6.     The resistance of 100 meter length of copper wire of 14SWG IS ‘X’ OHMS. The resistance of 100 of copper wire of 8 SWG will be

·        More than ‘x’ ohms

·        Equal to ‘x’ ohms

·        Less than ‘x’ ohms….

·        Equal to ‘x’ohms

7.     The colour code for 100 ohms resistor is

·        Black, Red, Orange

·        Red, Black, Red

·        Brown, Black, Brown…

·        Black, Black, Red

8.     The sequence of colour band on a 47 K ohm with ±5% tolerance resistor will be

·        Yellow, violet, yellow and gold

·        Yellow, violet, orange, and gold………..

·        Yellow, violet, orange and silver

·        Yellow, violet, brown and silver

9.     The power factor of a purely resistive circuit is

·        Zero

·        Unity…..

·        Lagging

·        leading

10.                        1 M ohm, 1 W resistance is likely to be a:

·        Wire wound resistor

·        Carbon resistor….

·        Rheostat

·        None of above

11.                        If three,30µF capacitance are connected in series. Find








MCQ s on Basic Electrical Engineering set 2 for Industrial Extension Officer,RRB JE, SSC JE,Sub Engineer Electrical, Line Man, Electrician MCQ s on Basic Electrical Engineering set 2 for Industrial Extension Officer,RRB JE, SSC JE,Sub Engineer Electrical, Line Man, Electrician Reviewed by Sikha on January 04, 2019 Rating: 5
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