Recent questions tagged electrical-engineering

What is phase angle in electrical engineering ?

Description : What is phase angle in electrical engineering ?

Last Answer : In electrical engineering, phase angle is the angular difference in phase between two sinusoidal waves or signals. It is typically measured in degrees or radians, and it represents the amount of shift or ... and current in an AC circuit can affect the power factor and the efficiency of the circuit.

A 3 phase 50 Hz induction motor has full load speed of 970 rpm. Calculate no of poles and slip frequency.

Description : A 3 phase 50 Hz induction motor has full load speed of 970 rpm. Calculate no of poles and slip frequency.

Last Answer : The number of poles in an induction motor can be calculated using the following formula: No. of poles = (120 * frequency) / speed In this case, the number of poles would be calculated as follows: No. of poles = ( ... ) - 50 Hz = 8.08 Hz So the motor has 6 poles and a slip frequency of 8.08 Hz.

ROM has a: a) Decoder followed by encoder b) Multiplexer followed by decoder c) Demultiplexer followed by an encoder d) None of the above

Description : ROM has a: a) Decoder followed by encoder b) Multiplexer followed by decoder c) Demultiplexer followed by an encoder d) None of the above

Last Answer : Ans: A

Which of the following is not a magnetic memory: a) Flip-flop b) Tape c) Drum d) Disk

Description : Which of the following is not a magnetic memory: a) Flip-flop b) Tape c) Drum d) Disk

Last Answer : Ans: A

The term 'Operating System' means: a) A set of programs which helps to display b) A set of programs which helps to control computer working c) Set of programs which helps to convert high level instructions to machine level instructions and vise-versa d) None of the above

Description : The term 'Operating System' means: a) A set of programs which helps to display b) A set of programs which helps to control computer working c) Set of programs which helps to convert high level instructions to machine level instructions and vise-versa d) None of the above

Last Answer : Ans: B

A micropocessor consists of: a) Arithmetic Logic Unit (ALU) b) Memories c) Input / Output devices d) All the above

Description : A micropocessor consists of: a) Arithmetic Logic Unit (ALU) b) Memories c) Input / Output devices d) All the above

Last Answer : Ans: A

Floppy disc is a: a) ROM b) Fast storage c) Flexible storage d) Permanent storage

Description : Floppy disc is a: a) ROM b) Fast storage c) Flexible storage d) Permanent storage

Last Answer : Ans: C

Central Processing Unit (CPU) of a computer consists of: a) Control and arithmetic logic unit and primary storage b) Control, clock and ROM c) Control, clock and RAM d) Control, ALU, RAM and ROM

Description : Central Processing Unit (CPU) of a computer consists of: a) Control and arithmetic logic unit and primary storage b) Control, clock and ROM c) Control, clock and RAM d) Control, ALU, RAM and ROM

Last Answer : Ans: A

Transmission efficiency of transmission line increases with the: a) Decrease in power factor and voltage b) Increases in power factor and voltage c) Increase in power factor and decrease in voltage d) Increase in the voltage but decrease in the power factor

Description : Transmission efficiency of transmission line increases with the: a) Decrease in power factor and voltage b) Increases in power factor and voltage c) Increase in power factor and decrease in voltage d) Increase in the voltage but decrease in the power factor

Last Answer : Ans: B

When is the Ferranti effect on long over head lines experienced? a) The lines are lightly loaded b) The lines are heavily loaded c) The lines are fully loaded d) The power factor is unity

Description : When is the Ferranti effect on long over head lines experienced? a) The lines are lightly loaded b) The lines are heavily loaded c) The lines are fully loaded d) The power factor is unity

Last Answer : Ans: A

Tunnel diode is a: a) Power diode b) Has light doping c) Has heavy doping d) Is a reverse recovery diode Ans: C 76.LEDs are fabricated from: a) Silicon b) Germanium c) Si or Ge d) Gallium arsenide

Description : Tunnel diode is a: a) Power diode b) Has light doping c) Has heavy doping d) Is a reverse recovery diode Ans: C 76.LEDs are fabricated from: a) Silicon b) Germanium c) Si or Ge d) Gallium arsenide

Last Answer : Ans: D

For highly doped diode: a) Zener breakdown is likely to take place b) Avalanche breakdown is likely to take place c) Either (a) or (b) can take place d) Neither (a) nor (b) can take place

Description : For highly doped diode: a) Zener breakdown is likely to take place b) Avalanche breakdown is likely to take place c) Either (a) or (b) can take place d) Neither (a) nor (b) can take place

Last Answer : Ans: A

In the depletion region in the P-N junction there are: a) No charges b) No current c) No mobile charges d) No electron

Description : In the depletion region in the P-N junction there are: a) No charges b) No current c) No mobile charges d) No electron

Last Answer : Ans: C

Junction breakdown occurs: a) With forward bias b) With reverse bias c) Under high temperature condition d) Because of excess heating of the diode

Description : Junction breakdown occurs: a) With forward bias b) With reverse bias c) Under high temperature condition d) Because of excess heating of the diode

Last Answer : Ans: B

Factors on which soil resistance depends: a) depth of the electrode b) moisture c) Nacl d) all the above

Description : Factors on which soil resistance depends: a) depth of the electrode b) moisture c) Nacl d) all the above

Last Answer : Ans: D

When earth fault occurs: a) voltage potential at the earth mat increases due to grounding b) voltage potential at the earth mat decreases due to grounding c) voltage potential at the earth mat remains zero irrespective of fault d) none of the above

Description : When earth fault occurs: a) voltage potential at the earth mat increases due to grounding b) voltage potential at the earth mat decreases due to grounding c) voltage potential at the earth mat remains zero irrespective of fault d) none of the above

Last Answer : Ans: A

Ground resistance should be designed such that: a) grounding resistance should be as low as possible b) grounding resistance should be as high as possible c) grounding resistance should be always zero d) none of the above

Description : Ground resistance should be designed such that: a) grounding resistance should be as low as possible b) grounding resistance should be as high as possible c) grounding resistance should be always zero d) none of the above

Last Answer : Ans: A

Average resistance of human body is: a) 500 ohms b) 1000 ohms c) 1500 ohms d) 2000 ohms

Description : Average resistance of human body is: a) 500 ohms b) 1000 ohms c) 1500 ohms d) 2000 ohms

Last Answer : Ans: B

Earth wire or ground wire is made of: a) copper b) aluminium c) iron d) galvanized steel

Description : Earth wire or ground wire is made of: a) copper b) aluminium c) iron d) galvanized steel

Last Answer : Ans: D

Which of the following bridge is frequency sensitive: a) Wheatstone bridge b) Maxwell bridge c) Anderson bridge d) Wien bridge

Description : Which of the following bridge is frequency sensitive: a) Wheatstone bridge b) Maxwell bridge c) Anderson bridge d) Wien bridge

Last Answer : Ans: C

Which of the following instruments have least torque/weight ratio: a) Dynamometer type b) PMMC c) Attraction type moving iron d) Repulsion type moving iron

Description : Which of the following instruments have least torque/weight ratio: a) Dynamometer type b) PMMC c) Attraction type moving iron d) Repulsion type moving iron

Last Answer : Ans: A

Electrostatic type instruments are mainly used for measurement of: a) Heavy currents b) Low currents c) Low voltages d) High voltages

Description : Electrostatic type instruments are mainly used for measurement of: a) Heavy currents b) Low currents c) Low voltages d) High voltages

Last Answer : Ans: D

The law that finds application in electrolysis is: a) Faraday's law b) Coulomb's law c) Ohm's law d) Lenz's law

Description : The law that finds application in electrolysis is: a) Faraday's law b) Coulomb's law c) Ohm's law d) Lenz's law

Last Answer : Ans: A

The emf of a primary cell depends upon the: a) Physical dimension of the cell b) Nature of the electrolyte c) Nature of the electrode d) Both (b) and (c)

Description : The emf of a primary cell depends upon the: a) Physical dimension of the cell b) Nature of the electrolyte c) Nature of the electrode d) Both (b) and (c)

Last Answer : Ans: D

The cell which is used as standard cell is: a) Dry cell b) Solar cell c) Mercury-Cadmium cell d) Zinc-Carbon cell

Description : The cell which is used as standard cell is: a) Dry cell b) Solar cell c) Mercury-Cadmium cell d) Zinc-Carbon cell

Last Answer : Ans: C

Two transformers of identical voltages but different capacities are operated in parallel, for satisfactory load sharing: a) Impedances should be equal b) Per unit impedance must be equal c) per unit impedance and X/R ratio must be equal d) Impedance and X/R ratio must be equal

Description : Two transformers of identical voltages but different capacities are operated in parallel, for satisfactory load sharing: a) Impedances should be equal b) Per unit impedance must be equal c) per unit impedance and X/R ratio must be equal d) Impedance and X/R ratio must be equal

Last Answer : Ans: C

In conversion of 3-phase to 2-phase supply with T connection, the transformation ratio of the teaser will be__ times to that of main transformer: a) 1.732 b) 1.15 c) 0.866 d) Unity

Description : In conversion of 3-phase to 2-phase supply with T connection, the transformation ratio of the teaser will be__ times to that of main transformer: a) 1.732 b) 1.15 c) 0.866 d) Unity

Last Answer : Ans: C

The harmonic currents in a power transformer does not cause increase in: a) Secondary voltage b) Core loss c) Copper loss d) Magnetic interference with protective relays

Description : The harmonic currents in a power transformer does not cause increase in: a) Secondary voltage b) Core loss c) Copper loss d) Magnetic interference with protective relays

Last Answer : Ans: A

An auto transformer is preferred over an ordinary two winding transformer due to: a) Safety of operation b) Availability of taps on secondary c) Copper savings d) All the above

Description : An auto transformer is preferred over an ordinary two winding transformer due to: a) Safety of operation b) Availability of taps on secondary c) Copper savings d) All the above

Last Answer : Ans: C

In a transformer, with closed magnetic coupling between primary and secondary __ will improve: a) Efficiency b) All day efficiency c) Regulation d) None of the above

Description : In a transformer, with closed magnetic coupling between primary and secondary __ will improve: a) Efficiency b) All day efficiency c) Regulation d) None of the above

Last Answer : Ans: C

Booster transformer should never: a) Have fuse in the HV winding b) Be left open circuited c) Be left closed circuited d) None of the above

Description : Booster transformer should never: a) Have fuse in the HV winding b) Be left open circuited c) Be left closed circuited d) None of the above

Last Answer : Ans: B

The rating of the Transformer __ when the supply frequency is increased: a) Remains unchanged b) Increases c) Decreases d) None of the above

Description : The rating of the Transformer __ when the supply frequency is increased: a) Remains unchanged b) Increases c) Decreases d) None of the above

Last Answer : Ans: B

Squirrel cage induction motor has a) Zero starting torque b) Very small starting torque c) Medium starting torque d) Very high starting torque

Description : Squirrel cage induction motor has a) Zero starting torque b) Very small starting torque c) Medium starting torque d) Very high starting torque

Last Answer : Ans: B

Emulsifier protection is associated with: a) Grounding protection b) Dielectric strength protection of cables and conductors c) Lightning protection d) Fire protection

Description : Emulsifier protection is associated with: a) Grounding protection b) Dielectric strength protection of cables and conductors c) Lightning protection d) Fire protection

Last Answer : Ans: D

Which of the following busbar arrangement is generally employed in distribution system: a) One-and-half breaker arrangement b) Main and transfer arrangement c) Ring main distribution system d) Single busbar arrangement system

Description : Which of the following busbar arrangement is generally employed in distribution system: a) One-and-half breaker arrangement b) Main and transfer arrangement c) Ring main distribution system d) Single busbar arrangement system

Last Answer : Ans: C

Which of the device is employed in substation to limit the short circuit current in the power system: a) Shunt condenser b) Reactor c) Series capacitor d) Shunt capacitor

Description : Which of the device is employed in substation to limit the short circuit current in the power system: a) Shunt condenser b) Reactor c) Series capacitor d) Shunt capacitor

Last Answer : Ans: B

In order to improve the power factor ___ device is employed in the substation a) Synchronous condenser b) Synchronous reactor c) Series Capacitors d) None of the above

Description : In order to improve the power factor ___ device is employed in the substation a) Synchronous condenser b) Synchronous reactor c) Series Capacitors d) None of the above

Last Answer : Ans: A

Stones are provided in the substation to: a) To avoid fire accident by draining oil from transformer if leaks b) To avoid growing of weeds and plants c) To provide insulation d) All the above

Description : Stones are provided in the substation to: a) To avoid fire accident by draining oil from transformer if leaks b) To avoid growing of weeds and plants c) To provide insulation d) All the above

Last Answer : Ans: D

Which of the following station is least efficient........ A.Nuclear power plant B.Diesel power station C.Thermal power station D.None of the above

Description : Which of the following station is least efficient........ A.Nuclear power plant B.Diesel power station C.Thermal power station D.None of the above

Last Answer : Ans: C

The cost of fuel transportation is maxmimun in........ A.Hydro-electric power plant B.Steam power plant C.Nuclear power plant D.90% - 95%

Description : The cost of fuel transportation is maxmimun in........ A.Hydro-electric power plant B.Steam power plant C.Nuclear power plant D.90% - 95%

Last Answer : Ans: B

Which of the following has highest diversity factor? a) Domestic lightning b) Commercial lightning c) Industrial power d) Domestic power

Description : Which of the following has highest diversity factor? a) Domestic lightning b) Commercial lightning c) Industrial power d) Domestic power

Last Answer : Ans: A

When load factor and diversity factor increases ___________ a) cost of electricity decreases b) cost of electricity also increases c) cost of electricity remains same d) cost of electricity increases exponential

Description : When load factor and diversity factor increases ___________ a) cost of electricity decreases b) cost of electricity also increases c) cost of electricity remains same d) cost of electricity increases exponential

Last Answer : Ans: A

Which of the following power plant have longest physical life? a) Thermal power plant b) Nuclear power plant c) Hydroelectric power plant d) Diesel power plant

Description : Which of the following power plant have longest physical life? a) Thermal power plant b) Nuclear power plant c) Hydroelectric power plant d) Diesel power plant

Last Answer : Ans: C

Which power plant has minimum operating cost? a) Hydroelectric power plant b) Thermal power plant c) Nuclear power plant d) Gas Turbine Power Plant Ans: A 42. Which of the following have highest operating cost? a) Hydroelectric power plant b) Thermal power plant c) Nuclear power plant d) Solar electric power plant

Description : Which power plant has minimum operating cost? a) Hydroelectric power plant b) Thermal power plant c) Nuclear power plant d) Gas Turbine Power Plant Ans: A 42. Which of the following have ... a) Hydroelectric power plant b) Thermal power plant c) Nuclear power plant d) Solar electric power plant

Last Answer : Ans: B

Specific gravity of diesel oil is (A) 0.84 (B) 1.14 (C) 2.7 (D) 3.8.

Description : Specific gravity of diesel oil is (A) 0.84 (B) 1.14 (C) 2.7 (D) 3.8.

Last Answer : Ans: A

Which temperature for a lubricating oil will be lowest ? (A) Flash point (B) Fire point (C) Pour point (D) Boiling

Description : Which temperature for a lubricating oil will be lowest ? (A) Flash point (B) Fire point (C) Pour point (D) Boiling

Last Answer : Ans: C

Steam pressures usually used in thermal power plants are (A) 5 kg/cm2 to 10 kg / cm2 (B) 50 kg/cm2 to 100 kg / cm2 (C) 110 kg/cm2 to 170 kg / cm2 (D) 200 kg/cm2 to 215 kg / cm2

Description : Steam pressures usually used in thermal power plants are (A) 5 kg/cm2 to 10 kg / cm2 (B) 50 kg/cm2 to 100 kg / cm2 (C) 110 kg/cm2 to 170 kg / cm2 (D) 200 kg/cm2 to 215 kg / cm2

Last Answer : Ans: C

The efficiency of a thermal power plant improves with (A) increased quantity of coal burnt (B) larger quantity of water used (C) lower load in the plant (D) use of high steam pressures.

Description : The efficiency of a thermal power plant improves with (A) increased quantity of coal burnt (B) larger quantity of water used (C) lower load in the plant (D) use of high steam pressures.

Last Answer : Ans: D

Critical pressure of water is (A) 1 kg / cm2 (B) 100 kg / cm2 (C) 155 kg / cm2 (D) 213.8 kg / cm2 .

Description : Critical pressure of water is (A) 1 kg / cm2 (B) 100 kg / cm2 (C) 155 kg / cm2 (D) 213.8 kg / cm2 .

Last Answer : Ans: D

Equipment used for pulverizing the coal is known as (A) Ball mill (B) Hopper (C) Burner (D) Stoker.

Description : Equipment used for pulverizing the coal is known as (A) Ball mill (B) Hopper (C) Burner (D) Stoker.

Last Answer : Ans: A

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