Mechanical Engineering MCQs – Diesel Engine & Gas Turbine Power Plants ( Power Plant Engineering ) MCQs
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Mechanical Engineering MCQs – Diesel Engine & Gas Turbine Power Plants ( Power Plant Engineering ) MCQs
The most occurred mcqs of ( ) in past papers. Past papers of Diesel Engine & Gas Turbine Power Plants ( Power Plant Engineering ) Mcqs. Past papers of Diesel Engine & Gas Turbine Power Plants ( Power Plant Engineering ) Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Diesel Engine & Gas Turbine Power Plants ( Power Plant Engineering ) Mcqs. The Important series of Diesel Engine & Gas Turbine Power Plants ( Power Plant Engineering ) Mcqs are given below:
Diesel Engine Basics
1. If the temperature of intake air in internal combustion engine increases, then its efficiency will __________
a) remain same
b) increase
c) decrease
d) none of the mentioned
Answer: c
Explanation: The efficiency of an IC Engine is inversely proportional to the temperature of intake air.
2. The operation of forcing additional air under pressure in the engine cylinder is known as __________
a) Supercharging
b) Scavenging
c) Turbulence
d) Pre-ignition
Answer: a
Explanation: Supercharging is the operation of forcing additional air under pressure in the engine cylinder.
3. The ignition quality of petrol is expressed by __________
a) Cetane number
b) Octane number
c) Calorific Value
d) None of the mentioned
Answer: b
Explanation: Octane number estimates the quality of petrol.
4. The mean effective pressure obtained from engine indicator indicates the __________
a) maximum pressure developed
b) minimum pressure developed
c) instantaneous pressure at any point
d) average pressure
Answer: d
Explanation: The mean effective pressure indicates the average pressure on the engine.
5. The probability of knocking in diesel engines is increased by __________
a) high self-ignition temperature
b) low volatility
c) high viscosity
d) all of the mentioned
Answer: d
Explanation: The probability of knocking in diesel engines is increased by keeping high self-ignition temperature, low volatility, high viscosity, etc.
6. Reactors for propulsion applications are designed for__________
a) any form of uranium
b) natural uranium
c) enriched uranium
d) thorium
Answer: c
Explanation: Enriched uranium is the material that is used for making reactors for propulsion application.
7. What is the pour point of fuel oil?
a) Minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame
b) Temperature at which it solidifies or congeals
c) It catches fire without external aid
d) Indicated by 90% distillation temperature i.e., when 90% of sample oil has distilled off
Answer: b
Explanation: The temperature at which fuel oil solidifies or congeals is called pour point of fuel oil.
8. What is the maximum temperature in the I.C. engine cylinder is of the order of(in degree Celsius)?
a) 500-1000
b) 1000-1500
c) 1500-2000
d) 2000-2500
Answer: d
Explanation: The maximum temperature in the I.C. engine cylinder is of the order of(in degree Celsius) is 2000-25000 degree Celsius.
9. In compression ignition engines, swirl denotes a __________
a) Haphazard motion of the gases in the chamber
b) Rotary motion of the gases in the chamber
c) Radial motion of the gases in the chamber
d) None of the mentioned
Answer: b
Explanation: Swirl in a compression ignition engine denotes rotary motion of the gases in the chamber.
10. Supercharging is the process of __________
a) Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere
b) Supplying compressed air to remove combustion products fully
c) Providing excess temperature to the sucked in gases
d) None of the mentioned
Answer: a
Explanation: Supercharging is the process of supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere.
11. The object of supercharging the engine is __________
a) to increase the power output of an engine when greater power is required
b) to reduce mass of the engine per brake power
c) to reduce space occupied by the engine
d) all of the mentioned
Answer: d
Explanation: Supercharging is done to increase the power output of an engine, to reduce mass of the engine per brake power & to reduce space occupied by the engine.
12. The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the __________
a) jet area is automatically varied depending on the suction
b) the flow from the main jet is diverted to the compensating jet with increase in speed
c) flow is produced due to the static head in the float chamber
d) the diameter of the jet is constant and the discharge coefficient is invariant
Answer: c
Explanation: The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the flow is produced due to the static head in the float chamber.
13. The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called?
a) overall efficiency
b) mechanical efficiency
c) relative efficiency
d) volumetric efficiency
Answer: d
Explanation: Volumetric Efficiency is the ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston.
14. A moderator generally used in nuclear power plants is?
a) heavy water
b) concrete
c) graphite & concrete
d) graphite
Answer: c
Explanation: A moderator generally used in nuclear power plants is made up of graphite & concrete.
15. In a diesel engine, the duration between the time of injection and ignition is known as?
a) delay period
b) period of ignition
c) burning period
d) pre-ignition period
Answer: a
Explanation: In a diesel engine, the duration between the time of injection and ignition, is known as the delay period.
Diesel Engine Types and their Applications – I
1. Nuclear Reactors are used __________
a) to produce heat for thermoelectric power
b) to propel ships, submarines, aircrafts
c) to produce fissionable material
d) all of the mentioned
Answer: d
Explanation: Nuclear reactors have wide range of usage which include producing heat for thermoelectric power, ship propulsion, production of fissionable materials, etc.
2. Where reactor operation is designed with fast neutrons such as in reactors using highly enriched fuel, the moderator used is?
a) Carbon dioxide
b) Heavy Water
c) Graphite
d) No moderator is needed
Answer: d
Explanation: Where reactor operation is designed with fast neutrons such as in reactors using highly enriched fuel, no moderator is required.
3. The expansion of fuel in a four stroke cycle diesel engine __________
a) starts at 15° after top dead centre and ends at 30° before bottom dead centre
b) starts at top dead centre and ends at 30° after top dead centre
c) may start and end anywhere
d) starts at 15° before top dead centre and ends at 30° after top dead centre
Answer: a
Explanation: The expansion of fuel in a four stroke cycle diesel engine starts at 15° after top dead centre and ends at 30° before bottom dead centre.
4. A moderator, in nuclear power plants, is a medium introduced into the fuel mass in order to __________
a) slow down the speed of fast moving neutrons
b) control the reaction
c) reduce the temperature
d) extract heat from nuclear reaction
Answer: a
Explanation: A moderator, in nuclear power plants, is a medium introduced into the fuel mass in order to slow down the speed of fast moving neutrons.
5. The thermal efficiency of diesel engines is about __________
a) 30%
b) 15%
c) 50%
d) 70%
Answer: d
Explanation: The thermal efficiency of diesel engines is about 70%.
6. In a four stroke cycle petrol engine, the charge is ignited at __________
a) 30° after bottom dead centre
b) 30° before bottom dead centre
c) 30° after top dead centre
d) 30° before top dead centre
Answer: d
Explanation: In a four stroke cycle petrol engine, the charge is ignited at 30° before top dead centre.
Hydroelectric Power Plant MCQs
7. The exhaust valve in a four stroke cycle petrol engine __________
a) opens at 50° after bottom dead centre and closes at 15° before top dead centre
b) opens at 50° before bottom dead centre and closes at 15° after top dead centre
c) opens at bottom dead centre and closes at top dead centre
d) may open and close anywhere
Answer: b
Explanation: The exhaust valve in a four stroke cycle petrol engine opens at 50° before bottom dead centre and closes at 15° after top dead centre.
8. The brake power of a diesel engine, keeping other parameters constant, can be increased by __________
a) increasing the pressure of intake air
b) decreasing the density of intake air
c) decreasing the pressure of intake air
d) increasing the temperature of intake air
Answer: a
Explanation: The brake power of a diesel engine, keeping other parameters constant, can be increased by increasing the pressure of intake air.
9. In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the __________
a) end of suction stroke
b) beginning of exhaust stroke
c) beginning of suction stroke
d) end of exhaust stroke
Answer: c
Explanation: In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the beginning of exhaust stroke.
10. The effective inhibitor of pre-ignition is __________
a) alcohol
b) lead
c) water
d) none of the mentioned
Answer: c
Explanation: Water is the most effective inhibitor of pre-ignition.
Diesel Engine Types and their Applications – II
1. The reference fuels for knock rating of spark ignition engines would include __________
a) normal octane and aniline
b) iso-octane and normal hexane
c) iso-octane and alpha-methyl naphthalene
d) normal heptane and iso-octane
Answer: d
Explanation: The reference fuels for knock rating of spark ignition engines would include normal heptane and iso-octane.
2. What is the purpose of testing an internal combustion engine?
a) to conform the data used in design, the validity of which may be doubtful
b) to satisfy the customer regarding the performance of the engine
c) to determine the information, which cannot be obtained by calculations
d) all of the mentioned
Answer: d
Explanation: The purpose of testing an internal combustion engine is to conform the data used in design, the validity of which may be doubtful; to satisfy the customer regarding the performance of the engine & to determine the information, which cannot be obtained by calculations.
3. Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to __________
a) overheated spark plug points
b) red hot carbon deposits on cylinder walls
c) cylinder walls being too hot
d) any of the mentioned
Answer: d
Explanation: Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to either overheated spark plug points, red hot carbon deposits on cylinder walls, & cylinder walls being too hot.
4. The thermal efficiency of a standard Otto cycle for a compression ratio of 5.5 will be __________
a) 20%
b) 25%
c) 50%
d) 55%
Answer: c
Explanation: The Thermal efficiency of a standard Otto cycle for a compression ratio r is given by,
N = 1 – (1/r1.4-1).
5. The fuels in order of decreasing knock tendency for spark ignition engines are __________
a) Paraffin, aromatic, napthene
b) Paraffin, napthene, aromatic
c) Napthene, aromatics, paraffin
d) Napthene, paraffin, aromatic
Answer: b
Explanation: The fuels in order of decreasing knock tendency for spark ignition engines are Paraffin, napthene, aromatic.
6. In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is __________ the atmospheric pressure.
a) equal to
b) below
c) above
d) middle
Answer: b
Explanation: In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is below the atmospheric pressure.
7. Solid fuel fabricated into various small shapes, which are assembled to form fuel elements, is in the form of __________
a) pallets
b) plates
c) pins
d) all of the mentioned
Answer: d
Explanation: Solid fuel fabricated into various small shapes are of the form of pallets, plates, pins, etc.
8. A diesel engine is __________ as compared to petrol engine, both running at rated load.
a) equally efficient
b) more efficient
c) less efficient
d) all of the mentioned
Answer: b
Explanation: A diesel engine is more efficient as compared to petrol engine, both running at rated load.
9. A higher compression ratio causes __________
a) increase in detonation
b) pre-ignition
c) an acceleration in the rate of combustion
d) any one of the mentioned
Answer: d
Explanation: A higher compression ratio causes increased detonation, increased rate of combustion & pre-ignition.
10. Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine?
a) inlet valve closing before bottom dead centre
b) inlet valve closing after bottom dead centre
c) inlet valve opening before top dead centre
d) exhaust valve closing after top dead centre
Answer: a
Explanation: Inlet valve closing before bottom dead centre would reduce the volumetric efficiency of a vertical compression ignition engine.
Diesel Engine Analysis
1. A fuel of cetane number 40 has the same ignition quality as a mixture of __________
a) 40% alpha methyl napthalene and 60% cetane
b) 40% cetane and 60% alpha methyl napthalene
c) 40% petrol and 60% diesel
d) 40% diesel and 60% petrol
Answer: b
Explanation: A fuel of cetane number 40 has the same ignition quality as a mixture of 40% cetane and 60% alpha methyl naphthalene.
2. The control rods in the control system of nuclear reactors are used to __________
a) control fuel consumption
b) absorb excess neutrons
c) control temperature
d) all of the mentioned
Answer: b
Explanation: The function of control rods is to absorb the excess neutrons released during fission.
3. The pressure at the end of compression, in petrol engines, is approximately __________
a) 10 bar
b) 20 bar
c) 25 bar
d) 35 bar
Answer: a
Explanation: The pressure at the end of compression, in petrol engines, is approximately 10 bar.
4. If the speed of the engine is increased, the indicated power will __________
a) increase
b) decrease
c) remain same
d) none of the mentioned
Answer: a
Explanation: The speed of the engine & indicated power are inter related as they are directly proportional to each other, so if one increases, the other also increases & vice-versa.
5. Number of working strokes per min. for a two stroke cycle engine are __________ the speed of the engine in r.p.m.
a) equal to
b) one-half
c) four-times
d) twice
Answer: a
Explanation: Number of working strokes per min. for a two stroke cycle engine are equal to the speed of the engine in rpm.
6. Reflector in nuclear power plants __________ neutron leakage.
a) increases
b) decreases
c) has no effect
d) all of the mentioned
Answer: b
Explanation: Reflector in nuclear power plants decreases neutron leakage.
7. In order to eliminate knocking in compression ignition engines, there should be __________
a) high self-ignition temperature of fuel
b) late auto-ignition
c) short delay period
d) low compression ratio
Answer: c
Explanation: In order to eliminate knocking in compression ignition engines, there should be a shorter delay period.
8. Which of the following statement is correct?
a) Compression ratio for petrol engines varies from 6 to 10
b) Petrol engines work on Otto cycle
c) Higher compression ratio in diesel engines results in higher pressures
d) All of the mentioned
Answer: d
Explanation: All the mentioned statements are correct.
9. The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to __________
a) inject fuel at a high velocity to facilitate atomisation
b) inject fuel in a chamber of high pressure at the end of compression stroke
c) ensure that penetration is not high
d) all of the mentioned
Answer: d
Explanation: The fuel injection is at a sufficiently higher pressure in order to inject fuel at a high velocity to facilitate atomisation, to inject fuel in a chamber of high pressure at the end of compression stroke & to ensure that penetration is not high.
10. The two reference fuels used for cetane rating are __________
a) cetane & iso-octane
b) cetane & normal heptane
c) cetane & alpha methyl naphthalene
d) cetane & tetra ethyl lead
Answer: c
Explanation: Cetane & alpha methyl naphthalene are the two reference fuels used for cetane rating.
11. In petrol engines, the delay period is of the order of __________
a) 0.001 sec
b) 0.002 sec
c) 0.003 sec
d) 0.004 sec
Answer: b
Explanation: The delay period in petrol engines is of the order of 0.002 sec.
12. How much voltage required to produce a spark across the gap, between the sparking points?
a) 2000-4000 volts
b) 4000-6000 volts
c) 6000-10000 volts
d) 10000-12000 volts
Answer: c
Explanation: The voltage required to produce a spark across the gap, between the sparking points is 6000-10000 Volts.
13. The scavenging efficiency of a tour stroke cycle diesel engine is __________
a) between 50-85%
b) between 95-100%
c) below 50%
d) between 85-95%
Answer: b
Explanation: The scavenging efficiency of a tour stroke cycle diesel engine is between 95-100%.
14. The specific fuel consumption per B.P. hour for a petrol engine is about __________
a) 0.2 kg
b) 0.25 kg
c) 0.3 kg
d) 0.35 kg
Answer: b
Explanation: The brake specific fuel consumption for a petrol engine is about 0.25 kg.
15. Which material is most commonly used for shielding?
a) Carbon
b) Concrete
c) Lead
d) All of the mentioned
Answer: c
Explanation: Lead is the material that is most commonly used for Shielding.