Important Current Electricity Notes for Students

Important Current Electricity Notes

Today we are going to Provide you Current Electricity Notes like Electromotive Force, Resistance, Ohm's Law, Electrical Energy etc.

What is Electromotive Force?
Electromotive Force (E.M.F.) is the force that causes a current of electricity to flow. The Volte is the unit of potential difference and electromotive force.


Current Electricity Notes

What is Resistance in Electrical Engineering?
The Opposition to the flow of electron is called electrical Resistance. Resistance may also be defined as "The property of the electric circuit which opposes the flow of current". The Practical Unit of Electrical Resistance is ohm.

What is Ohm's Law?
"For a fixed metal conductor, the temperature and other conditions remaining constant, the current I through it is proportional to the potential difference V between its ends".

in other words, V/I = Constant or V/I = R, where R is the resistance of the conductor between the two points.

Also See - Top Electrical Engineering MCQ on Simple DC Networks

What is Electrical Energy?
Electrical Energy is expressed in terms of KW (kilowatt = 1000W) or MW (megawatt = 1000 KW)

1 kWh = 1 kw * 1 hour = 1000 watt-hours (=1000*60*60 watt-sec.)

What is Linear and Non-linear Resistor?
Linear Resistor - A Linear resistor is one which obeys Ohm's law. A circuit which contains only linear components is called a linear circuit.

Non-linear Resistor - Such elements in which the V/I (volt-ampere) plots are not straight lines but curves are called non-linear resistors or non-linear elements.


What is the Limitation of Ohm's Law?
Ohm's law does not apply under the following conditions:
1. Electrolytes where enormous gases are produced on either electrode.
2. Non-linear resistors like vacuum radio valves, semi-conductors, gas-filled tubes etc.
3. Arc lamps.
4. Metals which get heated up due to the flow of current through.
5. Appliances like metal rectifiers, crystal detectors, etc. in which operation depends on the direction of the current.

Classification of Resistors
The resistors 'are classified as follows:

1. Fixed resistors - The fixed resistor is the simplest type of resistor. Fixed means that the unit is so constructed that its resistance value is constant and unchangeable. These are made of a carbon composition and have a cover of black or brown hard plastics.

2. Tapped resistors - A tapped resistor is a resistor which has a tap, or connection, somewhere along the resistance material. These resistors are usually wire wound type. If they have more than one tap, they will have a separate terminal for each.

Also See - Top 24 Basic Electrical Engineering Questions with Answers

3. Variable resistors - A variable resistor has a movable contact that is used to adjust or select the resistance value between two or more terminals. A variable resistor is commonly called a control.


4. Special resistors - The most common type of special resistors is the fusible type. A fusible resistor has a definite resistance value and it protects the circuit much like a fuse. Another special resistor is the temperature compensating unit. Such resistors are used to provide special control of the circuit that must be extremely stable in their operation.

We hope that this post "Important Current Electricity Notes for Students" will help you in your preparation. if you have any suggestion and request, you can tell us through comment here.


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What is Power/Electrical Engineering All Detail

What is Power Engineering

This Post is about What is Power or Electrical Engineering? If you wish to pursue careers in the field of engineering, then electrical or power engineering is Evergreen in case of possibilities and demand. There is a need for electrical engineers in every area from home to industrial and even in space applications.

What is Power Engineering
Due to the increasing use of modern machines and gadgets in our life, there is a need to make the devices more capable, manageable and reliable. Due to this increasing demand, the employment of electrical engineers is increasing.

What is the necessary qualification for Power or Electrical Engineering?

Intermediate is necessary from the science stream to study electrical engineering. After this, you can achieve a Bachelor Degree or Master degree beyond that in this course.

In what new areas are employment opportunities for Power/Electrical Engineers?

In recent times, the electrical engineering sector is spread fast in advanced technology areas like Semiconductor, Networking, Communications Navigation System, Computers and Data Analysis.


Research in Electrical/Power Engineering

Institutes and companies are also investing in research in new areas for the graduate of electrical engineering. In these areas, a lot of research project such as Distributed Grid Control, Smart Grid, source of non-conventional energy, oil and gas extraction from the ocean, can be found for electrical engineers.

Job in the Data Digitization Sector

Government and individuals are focusing on increasing special data digitization and networking. In this way, electrical graduates are most likely to get jobs in the field of network and communication. With the advancement in the field of communication, there are definitely a lot of digital data, which need to be analyzed. These vigorous systems of data collection have opened up many opportunities for electrical engineers.

We Hope You Enjoy Reading This Article about What is Power or Electrical Engineering If You want more Article like this Comment Below.

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Electrical Engineering Basics Questions with Answers Part 1

Electrical Engineering Basics Questions

Today we are Going to Provide You Electrical engineering interview questions from Electrical Engineering Basics Chapter.

All matter is composed of - Atoms

To be a conductor, the substance must contain some mobile electrons

Conductivity depends on the number of electrons. - (Yes/No)

The energy level of an electron decreases as its distance from the nucleus increases.  - (Yes/No)

Electrical Engineering Basics Questions


Atoms with fewer than four valence electrons are good conductors.



Atoms with more than four valence electrons are poor conductors.

Atoms with four valence electrons are - semi-conductors

Mass of an electron is approximately equal to 1/1000 mass of the proton - (Yes/No)

The diameter of an electron = 10-15 Meter (Yes/No)

When an electron is removed from a neutral atom, this atom becomes positively charged and is called a - Positive Ion

The controlled movement of electrons through a substance is called - Current

Electromotive force is the force that causes a current of electricity to flow.

Also Read - Basic of Electrical Engineering and Basic Electrical Formulas

The is a unit of potential difference and electromotive force - Volt

Electron-volt is a unit in terms of which the energies of atomic particles are expressed. (Yes/No)

The opposition to the flow of electrons is called electrical resistance

The practical unit of electric resistance is mho. (Yes/No)

Resistivity of a material may be defined as the resistance between the opposite faces of a meter cube of that material.


The reciprocal of specific resistance of a material is called its conductivity

The unit of conductivity is ohm/ meter. (Yes/No)

The resistance of metal conductors increases with rising of temperature. (Yes/No)

The resistance of semiconductors and all electrolytes decreases as the temperature rises.

A linear resistor is one which Obey's Ohm's law.

At very low temperature, some metals acquire zero electrical resistance and zero magnetic induction, the property known as super-conductivity

A fixed resistor is the simplest type of resistor and its value is constant and unchangeable.

Also ReadImportant Topic on A.C. Fundamentals

A variable resistor is commonly called a control. (Yes/No)

The most common type of special resistor is the fusible type. (Yes/No)

In a series combination of resistors, the current flowing through each resistor is different. (Yes/No

The resistivity of pure semiconductors is of the order of 1 ohm-meters. (Yes/No)

The symbol marked R8 represents a fixed resistor.

The part represented by the symbol marked R1 is a Variable resistor.

This is Part 1 of Electrical Engineering Basics Questions with Answers, these Questions and Answers are Very Important For Your Exam and Interview. Keep Visiting ElectricalNotes4u for Latest Electrical Engineering MCQ, Notes, Interview Questions with Answers.

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Top Electrical Engineering MCQ on Simple DC Networks

Top Electrical Engineering MCQ on Simple DC Networks

1 - In a series circuit, which of the parameters remain constant across all circuit elements such as resistor, capacitor and inductor etcetera?
a) Voltage
b) Current
c) Both voltage and current
d) Neither voltage nor current.

Answer: b
MCQ on Simple DC Networks

2 - If there are two bulbs connected in series and one blows out, what happens to the other bulb?
a) The other bulb continues to glow with the same brightness
b) The other bulb stops glowing
c) The other bulb glows with increased brightness
d) The other bulb also burns out

Answer: b

3 - Voltage across a series resistor circuit is proportional to?
a) The amount of time the circuit was on for
b) The value of the resistance itself
c) The value of the other resistances in the circuit
d) The power in the circuit

Answer: b

4 - Many resistors connected in series will?
a) Divide the voltage proportionally among all the resistors
b) Divide the current proportionally
c) Increase the source voltage in proportion to the values of the resistors
d) Reduce the power to zero

Answer: a

5 - What happens to the current in the series circuit if the resistance is doubled?
a) It becomes half its original value
b) It becomes double its original value
c) It becomes zero
d) It becomes infinity

Answer: a

Also Read - MCQ on Control System for Electrical Engineering

6 - If two bulbs are connected in parallel and one bulb blows out, what happens to the other bulb?
a) The other bulb blows out as well
b) The other bulb continues to glow with the same brightness
c) The other bulb glows with increased brightness
d) The other bulb stops glowing

Answer: b

7 - The current in each branch of a parallel circuit is proportional to_______
a) The amount of time the circuit is on for
b) Proportional to the value of the resistors
c) Equal in all branches
d) Proportional to the power in the circuit

Answer: b

8 - The currents in the three branches of a parallel circuit are 3A, 4A and 5A. What is the current leaving it?
a) 0A
b) Insufficient data provided
c) The largest one among the three values
d) 12A

Answer: d

9 - Batteries are generally connected in______
a) Series
b) Parallel
c) Either series or parallel
d) Neither series nor parallel

Answer: a

10 - What is the value of current if a 50C charge flows in a conductor over a period of 5 seconds?
a) 5A
b) 10A
c) 15A
d) 20A

Answer: b

11 - KCL can be applied for __________
a) Planar networks
b) Non-planar networks
c) Both planar and non-planar
d) Neither planar nor non-planar

Answer: c

12 - KVL is applied in ____________
a) Mesh analysis
b) Nodal analysis
c) Both mesh and nodal
d) Neither mesh nor nodal

Answer: a

13 - A 250V bulb passes a current of 0.3A. Calculate the power in the lamp.
a) 75W
b) 50W
c) 25W
d) 90W

Answer: a

14 - Kilowatt-hour(kWh) is a unit of?
a) Current
b) Power
c) Energy
d) Resistance

Answer: c

15 - Calculate the work done in a resistor of 20 ohm carrying 5A of current in 3 hours.
a) 1.5J
b) 15J
c) 1.5kWh
d) 15kWh

Answer: c

16 - The SI unit of power is?
a) kW(kilo-watt)
b) J/s(joules per second)
c) Ws(watt-second)
d) J/h(joules per hour

Answer: b

17 - Out of the following, which one is not a source of electrical energy?
a) Solar cell
b) Battery
c) Potentiometer
d) Generator

Answer: c

18 - A battery converts___________
a) Electrical energy to chemical energy
b) Chemical energy to electrical energy
c) Mechanical energy to electrical energy
d) Chemical energy to mechanical energy

Answer: b

19 - A wire of length 2m and another wire of length 5m are made up of the same material and have the same area of cross section, which wire has higher resistance?
a) Both have equal resistance
b) The 2m wire has higher resistance
c) The 5m wire has higher resistance
d) The value of resistance cannot be determined from the given data

Answer: c

20 - Which, among the following is a unit for resistivity?
a) ohm/metre
b) ohm/metre2
c) ohm-metre
d) ohm-metre2

Answer: c

21 - The reciprocal of resistivity is________
a) Conductance
b) Resistance
c) Conductivity
d) Impedance

Answer: c

22 - The resistance of pure metals ___________
a) Increases with increase in temperature
b) Decreases with increase in temperature
c) Remains the same with increase in temperature
d) Becomes zero with increase in temperature

Answer: a

23 - The temperature of a coil cannot be measured by which of the following methods?
a) Thermometer
b) Increase in resistance of the coil
c) Thermo-junctions embedded in the coil
d) Caloriemeter

Answer: d

24 - Materials having resistance almost equal to zero is_______
a) Semi-conductor
b) Conductor
c) Superconductors
d) Insulators

Answer: c
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Top 24 Basic Electrical Engineering Questions with Answers

Basic Electrical Engineering Questions with Answers


1- In a constant voltage DC circuit, when the resistance increases, the current will 
a) Decrease 
a) Stop 
a) Increase 
a) Remains constant 

Answer: a

2 - The unit of electrical resistance is 
a) Volt 
a) Amp 
a) Ohm 
a) Coulomb 

Answer: c
Basic Electrical Engineering Questions

3 - The current out of an ideal current source is 
a) Zero 
a) Constant 
a) Load resistance dependent 
a) Internal resistance dependent 

Answer: b



4 - In a series circuit, which of the parameters remain constant across all circuit elements such as resistor, capacitor and inductor etcetera? 
a) Voltage 
b) Current 
c) Both voltage and current 
d) Neither voltage nor current 

Answer: b

5 - If there are two bulbs connected in series and one blows out, what happens to the other bulb? 
a) The other bulb continues to glow with the same brightness 
b) The other bulb stops glowing 
c) The other bulb glows with increased brightness 
d) The other bulb also burns out
Answer: b

6 - What happens to the current in the series circuit if the resistance is doubled? 
a) It becomes half its original value 
b) It becomes double its original value 
c) It becomes zero 
d) It becomes infinity 

Answer: a

7 - The current in each branch of a parallel circuit is proportional to_______ 
a) The amount of time the circuit is on for 
b) Proportional to the value of the resistors 
c) Equal in all branches 
d) Proportional to the power in the circuit 

Answer: b

8 - The currents in the three branches of a parallel circuit are 3A, 4A and 5A. What is the current leaving it? 
a) 0A 
b) Insufficient data provided 
c) The largest one among the three values 
d) 12A 

Answer: d

9 - Batteries are generally connected in______ 
a) Series b) Parallel 
c) Either series or parallel 
d) Neither series nor parallel 

Answer: a

10 - What is the value of current if a 50C charge flows in a conductor over a period of 5 seconds? 
a) 5A 
b) 10A 
c) 15A 
d) 20A 

Answer: b

11 - KCL can be applied for __________ 
a) Planar networks 
b) Non-planar networks 
c) Both planar and non-planar 
d) Neither planar nor non-planar 

Answer: c

12 - What is the basic law that has to be followed in order to analyze ant circuit? 
a) Newton’s laws 
b) Faraday’s laws 
c) Ampere’s laws 
d) Kirchhoff’s law 

Answer: d



13 - KVL is applied in ____________ 
a) Mesh analysis 
b) Nodal analysis 
c) Both mesh and nodal 
d) Neither mesh nor nodal 

Answer: a

14 - A 250V bulb passes a current of 0.3A. Calculate the power in the lamp.
a) 75W
b) 50W
c) 25W
d) 90W

Answer: a

15 - Calculate the work done in a resistor of 20 ohm carrying 5A of current in 3 hours.
a) 1.5J
b) 15J
c) 1.5kWh
d) 15kWh

Answer: c

16 - The SI unit of power is?
a) kW(kilo-watt)
b) J/s(joules per second)
c) Ws(watt-second)
d) J/h(joules per hour

Answer: b

17 - Which among the following is a unit for electrical energy?
a) V(volt)
b) Wh(kilowatt-hour)
c) Ohm
d) C(coloumb)

Answer: b

18 - A battery converts___________
a) Electrical energy to chemical energy
b) Chemical energy to electrical energy
c) Mechanical energy to electrical energy
d) Chemical energy to mechanical energy

Answer: b

19 - Which of the following statements are true with regard to resistance?
a) Resistance is directly proportional to length of the wire
b) Resistance is directly proportional to area of cross section of the wire
c) Resistance is inversely proportional to the length of the wire
d) All the statements are false

Answer: a

20 - The reciprocal of resistivity is________
a) Conductance
b) Resistance
c) Conductivity
d) Impedance

Answer: c

21 - The resistance of insulators __________
a) Increases with increase in temperature
b) Decreases with increase in temperature
c) Remains the same with increase in temperature
d) Becomes zero with increase in temperature

Answer: b

22 - What is the unit of temperature coefficient?
a) ohm/centigrade
b) ohm-centigrade
c) centigrade-1
d) centigrade

Answer: c

23 - The rise or fall in resistance with the rise in temperature depends on________
a) The property of the conductor material
b) The current in the metal
c) Both the given options
d) Does not depend on any factor

Also Read - MCQ on Control System for Electrical Engineering

Answer: a

24 - Materials having resistance almost equal to zero is_______
a) Semi-conductor
b) Conductor
c) Superconductors
d) Insulators

Answer: c
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Most Asked Electrical Engineering Objective Question on Electric Heating

Most Asked Electrical Engineering Objective Question on Electric Heating

1. ______ method has leading power factor
(a) Resistance heating
(b) Dielectric heating
(c) Arc heating
(d) Induction heating
Ans: b

2. Heat is transferred simultaneously by condition, convection and radiation
(a) inside boiler furnaces
(b) during melting of ice
(c) through the surface of the insulted pipe carrying steam
(d) from refrigerator coils to freezer of a refrigerator
Ans: a

3. The process of heat transfer during the reentry of satellites and missiles, at very high speeds, into earth’s atmosphere is known as
(a) ablation
(b) radiation
(c) viscous dissipation
(d) irradiation
Ans: a

4. Which of the following has the highest value of thermal conductivity ?
(a) Water
(b) Steam
(c) Solid ice
(d) Melting ice
Ans: c


5. Which of the following insulating materials was suitable for low temperature applications ?
(a) Asbestos paper
(b) Diatomaceous earth
(c) 80 percent magnesia
(d) Cork
Ans: b

6. Which of the following will happen if the thickness of refractory wall of furnace is increased ?
(a) Heat loss through furnace wall will increase
(b) Temperature inside the furnace will fall
(c) Temperature on the outer surface of furnace walls will drop
(d) Energy consumption will increase
Ans: c

Also Read - MCQ on Cables for Electrical Engineering

7. In a resistance furnace the atmosphere is
(a) oxidising
(b) deoxidising
(c) reducing
(d) neutral
Ans: a

8. By the use of which of the following, high frequency power supply for induction furnaces can be obtained ?
(a) Coreless transformers
(b) Current transformers
(c) Motor-generator set
(d) Multi-phase transformer
Ans: c

9. In an electric room heat convector the method of heating used is
(a) arc heating
(b) resistance heating
(c) induction heating
(d) dielectric heating
Ans: b

10. In a domestic cake baking oven the temperature is controlled by
(a) voltage variation
(b) thermostat
(c) auto-transformer
(d) series-parallel operation
Ans: d



11. In resistance heating highest working temperature is obtained from heating elements made of
(a) nickel copper
(b) nichrome
(c) silicon carbide
(d) silver
Ans: c

12. In the indirect resistance heating method, maximum heat-transfer takes place by
(a) radiation
(b) convection
(c) conduction
(d) any of the above
Ans: a

13. Property of low temperature co-efficient of heating element is desired due to which of the following reasons ?
(a) To avoid initial rush of current
(b) To avoid change in kW rating with temperature
(c) Both (a) and (b)
(d) Either (a) or (b)
Ans: c

14. Radiations from a black body are proportional to
(a) T1
(b) T2
(c) T3
(d) T4
Ans: d

15. Ajax Wyatt furnace is started when
(a) it is filled below core level
(b) it is filled above core level
(c) it is fully empty
(d) none of the above
Ans: b

16. Radiant heating is used for which of the following ?
(a) Annealing of metals
(b) Melting of ferrous metals
(c) Heating of liquids in electric kettle
(d) Drying of paints and varnishes
Ans: d


17. Which of the following devices is necessarily required for automatic temperature control in a furnace ?
(a) Thermostat
(b) Thermocouple
(c) Auto-transformer
(d) Heating elements of variable resis-tance material
Ans: b

18. For radiant heating around 2250°C, the heating elements are made of
(a) copper alloy
(b) carbon
(c) tungsten alloy
(d) stainless steel alloy
Ans: c

19. The electrode of a direct arc furnace is made of
(a) tungsten
(b) graphite
(c) silver
(d) copper
Ans: b

20. In direct arc furnace, which of the following has high value ?
(a) Current
(b) Voltage
(c) Power factor
(d) All of the above
Ans: a

Tags-
#MCQ on Electric Heating
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Most Asked Electrical Engineering Objective Question on Industrial Drive

Most Asked Electrical Engineering Objective Question on Industrial Drive
1. Which of the following motors always starts on load ?
(a) Conveyor motor
(b) Floor mill motor
(c) Fan motor
(d) All of the above
Ans: d

2. When the load is above _____ a synchronous motor is found to be more economical.
(a) 2 kW
(b) 20 kW
(c) 50 kW
(d) 100 kW
Ans: d

3. The load cycle for a motor driving a power press will be
(a) variable load
(b) continuous
(c) continuous but periodical
(d) intermittent and variable load
Ans: d

4. While selecting an electric motor for a floor mill, which electrical characteristics will be of least significance ?
(a) Running characteristics
(b) Starting characteristics
(c) Efficiency
(d) Braking
Ans: d

5. Which of the following motors are preferred for overhead travelling cranes ?
(a) Slow speed motors
(b) Continuous duty motors
(c) Short time rated motors
(d) None of the above
Ans: c

Also Read - Basic of Electrical Engineering and Basic Electrical Formulas

6. ____ is preferred for synthetic fiber mills.
(a) Synchronous motor
(b) Reluctance motor
(c) Series motor
(d) Shunt motor
Ans: b

7. Ward-Leonard controlled D.C. drives are generally used for ______ excavators.
(a) Light duty
(b) Medium duty
(c) Heavy duty
(d) All of the above
Ans: c

8. Which of the following motors is used for elevators ?
(a) Induction motor
(b) Synchronous motor
(c) Capacitor start single phase motor
(d) Any of the above
Ans: a

9. Which part of a motor needs maximum attention for maintenance ?
(a) Frame
(b) Rearing
(c) Stator winding
(d) Rotor winding
Ans: b

10. _______ motor is a constant speed motor.
(a) Synchronous motor
(b) Schrage motor
(c) Induction motor
(d) Universal motor
Ans: a

11. The starting torque in case of centrifugal pumps is generally
(a) less than running torque
(b) same as running torque
(c) slightly more than running torque
(d) double the running torque
Ans: a

12. For which of the following applications D.C. motors are still preferred ?
(a) High efficiency operation
(b) Reversibility
(c) Variable speed drive
(d) High starting torque
Ans: c

13. In a paper mill where constant speed is required
(a) synchronous motors are preferred
(b) A.C. motors are preferred
(c) individual drive is preferred
(d) group drive is preferred
Ans: c

14. A reluctance motor
(a) is provided with slip rings
(b) requires starting gear
(c) has high cost
(d) is compact
Ans: d

15. The size of an excavator is usually expressed in terms of
(a) ‘crowd’ motion
(b) angle of swing
(c) cubic metres
(d) travel in metres
Ans: c

16. For blowers which of the following motor is preferred ?
(a) D.C. series motor
(b) D.C. shunt motor
(c) Squirrel cage induction motor
(d) Wound rotor induction motor
Ans: c

17. Which of the following is essentially needed while selecting a motor ?
(a) Pulley
(b) Starter
(c) Foundation pedal
(d) Bearings
Ans: b

18. ____ method of starting a three phase induction motor needs six terminals.
(a) Star-delta
(b) Resistance starting
(c) Auto-transformer
(d) None of the above
Ans: a


19. In ______ method of staging three phase induction motors the starting voltage is not reduced.
(a) auto-transformer
(b) star-delta
(c) slip ring
(d) any of the above
Ans: c

20. In jaw crushers a motor has to often start against ______ load.
(a) heavy
(b) medium
(c) normal
(d) low
Ans: a

21. Heat control switches are used in
(a) transformers
(b) cooling ranges
(c) three phase induction motors
(d) single phase
Ans: b

22. has relatively wider range of speed control.
(a) Synchronous motor
(b) Ship ring induction motor
(c) Squirrel cage induction motor
(d) D.C. shunt motor
Ans: d

23. In squirrel cage induction motors which of the following methods of starting cannot be used ?
(a) Resistance in rotor circuit
(b) Resistance in stator circuit
(c) Auto-transformer starting
(d) Star-delta starting
Ans: a

24. Battery operated scooter for braking uses
(a) plugging
(b) mechanical braking
(c) regenerative braking
(d) rheostatic braking
Ans: b

25. _____ has the least value of starting torque to full load torque ratio.
(a) D.C. shunt motor
(b) D.C. series motor
(c) Squirrel cage induction motor
(d) Slip ring induction motor
Ans: c

26. In case of _______ speed control by injecting e.m.f. in the rotor circuit is possible.
(a) d.c. shunt motor
(b) schrage motor
(c) synchronous motor
(d) slip ring induction motor
Ans: d

27. A pony motor is used for the starting which of the following motors ?
(a) Squirel cage induction motor
(b) Schrage motor
(c) Synchronous motor
(d) None of the above
Ans: c

28. In ________ the speed can be varied by changing the position of brushes.
(a) slip ring motor
(b) schrage motor
(c) induction motor
(d) repulsion motor
Ans: b

29. The travelling speed of cranes varies from
(a) 20 to 30 m/s
(b) 10 to 15 m/s
(c) 5 to 10 m/s
(d) 1 to 2.5 m/s
Ans: d

30. Besides a constant speed a synchronous rotor possesses which of the following advantages ?
(a) Lower cost
(b) Better efficiency
(c) High power factor
(d) All of the above
Ans: c

31. A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is
(a) slop speed operation
(b) high starting torque
(c) low windage losses
(d) all of the above
Ans: b

32. Which of the following motors has series characteristics ?
(a) Shaded pole motor
(b) Repulsion motor
(c) Capacitor start motor
(d) None of the above
Ans: b

33. For a D.C. shunt motor which of the following is incorrect ?
(a) Unsuitable for heavy duty starting
(b) Torque varies as armature current
(c) Torque-armature current is a straight line
(d) Torque is zero for zero armature current
Ans: a

34. For which of the following applications motor has to start with high acceleration?
(a) Oil expeller
(b) Floor mill
(c) Lifts and hoists
(d) Centrifugal pump
Ans: c

Also Read - MCQ on Measurement and Instrumentation for Electrical Engineering

35. Which of the following types of motor enclosure is safest ?
(a) Totally enclosed
(b) Totally enclosed fan cooled
(c) Open type
(d) Semi closed
Ans: b

36. The diameter of the rotor shaft for an electric motor depends on which of the following ?
(a) r.p.m. only
(b) Horse power only
(c) Horse power and r.p.m.
(d) Horse power, r.p.m. and power factor
Ans: c

37. The cost of an induction motor will increase as
(a) horsepower rating increases but r.p.m. decreases
(b) horsepower rating decreases but r.p.m. increases
(c) horsepower rating and operating speed increases
(d) horsepower rating and operating speed decreases
Ans: a


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