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Tuesday 23 January 2018

Electrical Engineering MCQ Multiple Choice Questions and Answers 31-45

  Author : shiva raj   1 comment
January 23, 2018

Multiple Choice Questions of Electric Current and Ohm's Law (31-45)

Electrical Engineering MCQ 31 TO 45
Multiple Choice Questions and Answers
Latest Electrical Interview Questions and Answers List




31.Which method can be used for absolute measurement of resistances ?

(A)Ohm's law method

(B)Wheatstone bridge method

(C)Releigh method

(D) Lortentz method.

32.Three 3 ohm resistors are connected to form a triangle. What is the resistance between any two of the corners?

(A) 3 / 4 ohms

(B) 3 ohms

(C) 2 ohms

(D) 4/3 ohm.


33.Five resistances are connected as shown in figure below. The equivalent resistance between the points A and B will be

(A) 35 ohms

(B) 25 ohms

(C) 15 ohms

(D) 5 ohms.


34.How many different combinations may be obtained with three resistors, each having the resistance R ?

(A) 3

(B) 4

(C) 5

(D) 6.

35.A wire of 0.14 mm diameter and specific resistance 9.6 micro ohm-cm is 440 cm long. The resistance of the wire will be

(A) 9.6 ohm

(B) 11.3 ohm

(C) 13.7 ohm

(D) 27.4 ohm.



36.Ohm's law is not applicable to

(A) DC circuits

(B) high currents

(C) small resistors

(D) semi-conductors.



37.A metal resistor has resistance of 10 ohm at 0°C and 11 ohms at 160°C, the temperature coefficient is

(A) 0.00625 / °C

(B) 0.0625 /°C

(C) 0.000625 /°C

(D) 0.625 /°C.



Questions 38 to 40 refer to Figure given below.

Five resistances are connected as shown and the combination is connected to a 40 V supply.

38. Voltage between point P and Q will be

(A) 40 V

(B) 22.5 V

(C) 20 V

(D) 17.5 V.



39.The current in 4 ohm resistor will be

(A) 2.1 A

(B) 2.7 A

(C) 3.0 A

(D) 3.5 A.



40.Least current will flow through

(A) 25 ohm resistor

(B) 18 ohm resistor

(C) 10 ohm resistor

(D) 5 ohm resistor.



41.Total power loss in the circuit is

(A)10W

(B) 50.2 W

(C) 205 W 

(D) 410 W.



42.A resistance of 5 ohms is further drawn so that its length becomes double. Its resistance will now be

(A) 5 ohms

(B) 7.5 ohms

(C) 10 ohms

(D) 20 ohms.



43.Specific resistance of a substance is measured in

(A) ohms

(B) mhos

(C) ohm-cm 

(D) cm/ohm.



44.A wire of resistance R has it length and cross-section both doubled. Its resistance will become

(A) 4 R

(B)2 R

(C) R 

(D) R / 4.



45.Ohm's law is not applicable in all the following cases Except

(A) Electrolytes

(B) Arc lamps

(C) Insulators 

(D) Vacuum ratio values.

More MCQs

Basic Electrical MCQs ->  1 TO 15
Basic Electrical MCQs -> 16 TO 30 
Basic Electrical MCQs -> 46 TO 60      



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Monday 22 January 2018

Electrical Engineering MCQ Multiple Choice Questions and Answers 46-60

  Author : shiva raj   No comments
January 22, 2018

Multiple Choice Questions of Electric Current and Ohm's Law (46-60)

Electrical Engineering MCQ 46 TO 60
Multiple Choice Questions and Answers
Latest Electrical Interview Questions and Answers List


46.The element of electric heater is made of

(A) copper

(B) steel

(C) carbon

(D) nichrome.



47. 5xl016 electrons pass across the section of a conductor in 1 minute 20 sec. The current flowing is

(A) 1mA

(B) 0.1 mA.

(C) 0.01mA

(D) 10 mA



48.Which of the following figures represents the effect of temperature on resistance for copper ?


(A) figure A.

(B) figure B

(C) figure C

(D) figure D



49.Three elements having conductance G1, G2 and G3 are connected in parallel. Their combined conductance will be

(A) 1/( 1/G1 + 1/G2 + 1/G3)

(B) (G1G2 + G2G3 + G3G1)/(G1 + G2 + G3)

(C) 1/(G1 + G2+ G3)

(D) G1 + G2 +G3.



Questions 50 to 53 refer to Figure given below:


50.The variation of resistance of iron and some alloys with temperature is shown in figure. The variation of carbon will be represented by

(A) curve A

(B) curve B.

(C) curve C

(D) curve D



51.Curves A and B represent the properties for materials which have

(A) low resistance

(B) low conductance

(C) negative resistance

(D) negative temperature coefficient.



52.Which of the following has negative temperature coefficient ?

(A) Brass

(B) Mercury

(C) Electrolytes.

(D) Silver


53.All of the following have negative temperature coefficient EXCEPT

(A) Paper

(B) Gold.

(C) Rubber.


54.For the circuit shown below the current I flowing through the circuit will be


(A)1 / 2 A

(B) 1 A

(C) 2 A.

(D) 4 A



55.A cube of material of side 1 cm has a resistance of 0.002 ohm between its opposite faces. If the same volume of the material has a length of 8 cm and a uniform cross-section, the resistance of this length will be

(A) 0.032 ohm

(B) 0.064 ohm

(C) 0.096 ohm

(D) 0.128 ohm.



56.A standard 60 W bulb is in series with a room heater and connected across the mains. If the 60 W bulb is replaced by 100 W bulb

(A) the heater output will increase.

(B) the heater output will reduce

(C) the heater output will remains unaltered


57. Two aluminium conductors have equal length. The cross-sectional area of one conductor is four times that of the other. If the conductor having smaller cross-sectional area has a resistance of 100 ohms the resistance of other conductor will be

(A) 400 ohms

(B) 100 ohms

(C) 50 ohms

(D) 25 ohms.


58.A nichrome wire used as heater coil has the resistance of 1 ohm/m. For a heater of 1000 W at 200 V, the length of wire required will be

(A) 10 m

(B) 20 m

(C) 40 m.

(D) 80 m


59.The hot resistance of a tungsten lamp is about 10 times the cold resistance. Accordingly, cold resistance of a 100 W, 200 V lamp will be 

(A) 4000 ohm

(B)400 ohm

(C)40 ohm.

(D)4 ohm


60. Variable resistors are

(A)Wire wound resistors.

(B)Thin film resistors

(C)Thick film resistors

(D)All of the above.


Here You Can Also Read:
Basic Electrical MCQs ->  1 TO 15
Basic Electrical MCQs -> 16 TO 30 
Basic Electrical MCQs -> 31 TO 45



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Friday 19 January 2018

Electrical Engineering MCQ Multiple Choice Questions and Answers 16-30

  Author : shiva raj   1 comment
January 19, 2018

Multiple Choice Questions of Electric Current and Ohm's Law (16-30):

Electrical Engineering MCQ 16 TO 30
Multiple Choice Questions and Answers
Latest Electrical Interview Questions and Answers List




16.Conductance is expressed in terms of

(A) ohm / m

(B) m / ohm

(C) mho / m

(D) mho.


17. Which of the following could be the value of resistivity of copper?

(A) 1.7 x 10-8 ohm-cm

 (B). 1.7 x 10-6 ohm-cm

(C). 1.6 x 10-5 ohm-cm

(D). 1.7 x 10-4 ohm-cm


18. A copper wire of length l and diameter d has potential difference V applied at its two ends. The drift velocity is vd. If the diameter of wire is made d/3, then drift velocity becomes

(A) 9 vd

(B) vd / 9

(C)vd /3

(D)vd.


19.Two resistances R1 and R2 give combined resistance of 4.5 ohms when in series and 1 ohm when in parallel. The resistances are

(A)3 ohms and 6 ohms

(B)3 ohms and 9 ohms

(C)1.5 ohms and 3 ohms

(D)1.5 ohms and 0.5 ohms.



20. We have three resistances of values 2 Ω, 3 Ω and 6 Ω. Which of the following combination will give an effective resistance of 4 Ω?

(A) All the three resistances in parallel

(B) 2 Ω resistance in series with parallel combination of 3 Ω and 6 Ω resistance

(C) 3 Ω resistance in series with parallel combination of 2 Ω and 6 Ω resistance

(D) 6 Ω resistance in series with parallel combination of 2 Ω and 3 Ω resistance.


21. Three equal resistors connected in series across a source of emf together dissipate 10 watts of power. What would be the power dissipated in the same resistors when they are connected in parallel across the same source of emf?

(A) 10 watts

(B) 30 watts

(C) 90 watts

(D) 270 watts.


22.Current I in the figure is




(A)1.5A

(B)0.5A

(C)3.5A

(D)2.5A


23.Four identical resistors are first connected in parallel and then in series. The resultant resistance of the first combination to the second will be

(A) 1 / 16 times

(B) 1 / 4 times

(C) 4 times

(D) 16 times.

24.Twelve wires of same length and same cross-section are connected in the form of a cube as shown in figure below. If the resistance of each wire is R, then the effective resistance between P and Q will be


(A)R

 (B) 5 / 6 R

(C) 3 / 4 R

(D) 4 / 3 R.


25. When P = Power, V = Voltage, I = Current, R = Resistance and G = Conductance, which of the following relation is incorrect?

(A) V = √ (PR)

(B). P= V2G

(C) G= P / I2

(D) I =√ (P / R)


26.The unit of electrical conductivity is

(A) mho / metre

(B) mho / sq. m

(C) ohm / metre

(D) ohm / sq. m.


27.Which of the following bulbs will have the least resistance ?

(A) 220 V, 60 W

(B) 220 V, 100 W

(C) 115 V, 60 W

(D) 115 V, 100 W.


28.The ratio of the resistance of a 100 W, 220 V lamp to that of a 100 W, 110 V lamp will be nearly

(A) 4

(B)2

(C) 1 / 2

(D) 1 / 4


29.The resistance of a 100 W, 200 V lamp is

(A) 100 ohm

(B) 200 ohm

(C) 400 ohm

(D) 1600 ohm.


30.Two 1 kilo ohm, 1/2 W resistors are connected in series. Their combined resistance value and wattage will be

(A) 2 kΩ, 1/2 W

(B) 2 kΩ, 1 W

(C) 2 kΩ, 2 W

(D) l kΩ, 1/2 W.



Here you can also read More important MCQs

Basic Electric MCQs 1 TO 15
Basic Electric MCQs 16 TO 30
Transformer MCQs 1 TO 20

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Thursday 18 January 2018

Electrical Engineering MCQ Multiple Choice Questions and Answers 1-15

  Author : shiva raj   4 comments
January 18, 2018

Multiple Choice Questions of Electric Current and Ohm's Law (1-15):


Electrical Engineering MCQ 1 TO 15
Multiple Choice Questions and Answers
Latest Transformers Interview Questions and Answers List


1.Resistivity of a wire depends on
(A) length
(B) material
(C) cross section area
(D) none of the above.

2. When n resistances each of value r are connected in parallel, then resultant resistance is x. When these n resistances are connected in series, total resistance is
(A) nx
(B) rnx
(C) x / n
(D) n2 x.

3. Resistance of a wire is r ohms. The wire is stretched to double its length, then its resistance in ohms is
(A) r / 2
(B) 4 r
(C) 2 r
(D) r / 4.

4. Kirchhoff's second law is based on law of conservation of
(A) charge
(B) energy
(C) momentum
(D) mass.

5. The diameter of the nucleus of an atom is of the order of
(A) 10 -31 m
(B) 10 -25 m
(C) 10 -21 m
(D) 10 -14m.

6. The mass of proton is roughly how many times the mass of an electron?
(A) 184,000
(B) 184,00
(C) 1840
(D)184.

7. The charge on an electron is known to be 1.6 x 10-19 coulomb. In a circuit the current flowing is 1 A. How many electrons will be flowing through the circuit in a second?
(A) 1.6 x 1019
(B) 1.6 x 10-19
(C) 0.625 x 1019
(D) 0.625 x 1012.

8. Two bulbs marked 200 watt-250 volts and 100 watt-250 volts are joined in series to 250 volts supply. Power consumed in circuit is
(A) 33 watt
(B) 67 watt
(C) 100 watt
(D) 300 watt.

9. Ampere second could be the unit of
(A) power
(B) conductance
(C) energy
(D) charge.

10. Which of the following is not the same as watt?
(A) joule/sec
(B) amperes/volt
(C) amperes x volts
(D) ( amperes )2 x ohm.

11. One kilowatt hour of electrical energy is the same as
(A) 36 x 105 watts
(B) 36 x 10s ergs
(C) 36 x 105 joules
(D) 36 x 105 B.T.U.

12. An electric current of 5 A is same as
(A) 5 J / C
(B) 5 V / C
(C) 5 C / sec
(D) 5 w / sec.

13. An electron of mass m kg and having a charge of e coulombs travels from rest through a potential difference of V volts. Its kinetic energy will be 
(A) eV Joules
(B) meV Joules
(C)me / V Joules
(D)V / me Joules.

14. The value of the following is given by 100 (kilo ampere ) x ( micro ampere ) 100 milli ampere * 10 ampere
(A) 0.001 A
(B) 0.1 A
(C) 1 A
(D) 10A.

15. A circuit contains two un-equal resistances in parallel
(A) current is same in both
(B) large current flows in larger resistor
(C) potential difference across each is same
(D) smaller resistance has smaller conductance.


 Basic Electrical MCQs 16 to 30    Transformer MCQs 21 to 40

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Monday 8 January 2018

Atom A Smallest Particle of Matter

  Author : shiva raj   No comments
January 08, 2018

Atom A Smallest Particle of Matter

A matter ex. copper,silicon,carbon,iron are the combination of multiple small particles of Atom.Every matters may be solid liquid or gas, all of these having smallest particles called as Atom.


 the above figure shows helium atom. At the centre of any atom has nucleus. Nucleus consist number of proton and neutron in same quantity. 99.94% mass of atom consist in nucleus.
The black cloud shows the electron.due to very high electron circulate around nucleus ,electron seen as cloud and blur at outer to inner.

Part of Atom: Neutron,Proton and Electron


  • Neutron: It present at centre of atom with proton with same number of quantity. it have no charge means it is neutral.(No-Charge)
  • Proton: It present at the centre of atom with same no. of  Neutron. It Have positive charged.  (+ve Charged)
  • electron: It present outside of nucleus and circulate around. Speed of circulation is very high hence it seen as cloud.It have Negative Charge(-ve Charged)

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Electrical Fundamentals

  Author : shiva raj   No comments
January 08, 2018

Electrical Fundamentals

In electrical fundamentals topic you learn about
  • what is electricity
  • electric charge
  • electric current
  • type of current
  • electric voltage
1-What is electricity: Electricity is a type of energy which have power. But electrical energy directly not used in any application, electrical energy is generally converted into another form of energy or force. 
for example:
when we supply electrical energy to a motor, there in electrical energy converted to electromagnetic energy which produced magnetic field in motor. Now electromagnetic flux/field produce torque in motor then motor run.
more examples: electrical convert to light (device light display etc)
electrical to sound, electrical to torque, electrical to electromagnetic field etc.

2-Electric charge: Electric charge is a property of an electron. there are two type of charge exist in an atom one is protones consist positive charge and another is electron consist Negative charge. And Neutron are neutral in nuclear present in center of an atom.
You know electric current flows in only good conductor this is due to electron and proton present in an atom. if electron and proton is same then no electron flow this material called bad conductor.if electron is more than proton then it is good conductor or vice-versa.
unit: coulomb
3-Electric current: Electric current is flow of electron in a conductor.When electron of an atom is flow in any one direction then it is called as electric current flow in conductor.
Electric current flow in material which have free electron. And free electron are available in only good conductors .overall to know, electron flow in conductor is current.
unit: Ampare

4-Current are two type: AC And DC
AC current: The current which change direction sinusoidal with time is Alternating current.
DC current: The current which not change direction with time is Direct current.
5-Electric voltage: Electric voltage is potential difference between two source.It is also called emf,voltage,potential difference. unit is volt.
Voltage produces flow of current. Current flow in direction from high potential source to low potential source. ex. current flow from positIve to negative direction in case of DC . In case of AC current flow from phase wire to ground or earth.




best example is lightning, when cloud spark then always electrical charges drop down to earth because earth has approximately zero potential.
As shown in above figure electron flow from negative charge to positive charge.but direction of current consider as always opposite to it.Mean current flow from positive to negative direction.


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Torque-slip characteristic for a three phase induction motor

Relation between torque and slip torque / slip curve is shown in figure: fig. Torque-slip characteristic  For range s=0 to s=1 wit...