Category: Steam and Gas Turbines Objective Questions

Steam and Gas Turbines Multiple Choice Questions on “Automatic Extraction Turbines”.

1. Extraction turbines has an opening in its casing.
a) True
b) False
Answer: a
Clarification: Extraction steam turbines has an opening in its casing.

2. __________ steam is moved to condenser from the turbine in a single step.
a) Total
b) partial
c) depends on load
d) none of the mentioned
Answer: b
Clarification: Some of the steam is extracted at intermediate pressure from casing and the remaining steam is sent to condenser.

3. The steam extraction is __________ extracted.
a) automatically
b) manually
c) automatically or manually
d) none of the mentioned
Answer: c
Clarification: The steam extraction may or may not be automatically extracted.

4. Regulated extraction _________ the total electricity produced.
a) reduces
b) increases
c) has no effect on
d) none of the mentioned
Answer: b
Clarification: Regulated extraction increases the additional electricity produced by steam extraction from casing.

5. Each extracting points on the casing has ______ temperature.
a) different
b) same
c) depends on the load
d) none of the mentioned
Answer: a
Clarification: At each extracting point there will be a different pressure and hence temperature also changes.

6. Each extracting points on the casing has _______ pressure.
a) same
b) different
c) depends on the load
d) none of the mentioned
Answer: b
Clarification: Each extracting point on the casing has a different temperature and pressure.

7. Automatic extraction turbines generate electrical energy.
a) True
b) False
Answer: a
Clarification: Automatic extraction turbines generate both electrical and thermal energy.

8. Automatic extraction turbine generate __________
a) mechanical & thermal energy
b) mechanical energy
c) thermal energy
d) none of the mentioned
Answer: c
Clarification: Automatic extraction turbine generate both electrical and thermal energy.

9. __________ extraction turbines are combined heat and power supply turbines.
a) Automatic
b) Manual
c) Manual or Automatic
d) None of the mentioned
Answer: a
Clarification: Combined heat and power supply turbines are classified as automatic extraction turbines,back pressure turbines and back pressure extraction turbines.

10. In automatic extraction turbines pressure of extracted steam is maintained by __________
a) Extraction points on case
b) Control system
c) Extraction points on case and Control system
d) None of the mentioned
Answer: b
Clarification: In automatic extraction turbines pressure of extracted steam is maintained by control system.

Steam and Gas Turbines Quiz on “Physical Characteristics of Combustion and Reactive Mixtures, Pressure Losses”.

1. Inert character of nitrogen __________ the commercial value of gas.
a) decreases
b) increases
c) remains same
d) none of the mentioned
Answer: a
Clarification: Inert character of nitrogen decreases the commercial value of gas. Inert gases can not be used in all circumstances.

2. Carbon dioxide released is __________ in nature.
a) not corrosive
b) corrosive
c) depends on the usage
d) none of the mentioned
Answer: b
Clarification: Carbon dioxide released from combustion has corrosive properties.

3. Hydrogen sulfide released during combustion is __________ in nature.
a) not corrosive
b) corrosive
c) depends on the usage
d) none of the mentioned
Answer: b
Clarification: Hydrogen sulfide released during combustion have corrosive properties.

4. In combustion it is assumed that there is ____________
a) atomic attraction
b) no atomic attraction
c) molecular attraction
d) none of the mentioned
Answer: a
Clarification: From kinetic theory of gases it is assumed that atomic attractions are negligible.

5. In combustion it is assumed that the number of molecules for unit volume is ___________
a) constant
b) decreased
c) increased
d) none of the mentioned
Answer: c
Clarification: From kinetic theory of gases it is assumed that the number of molecules for unit volume are constant. Volume and density does not change on phase change is occurred.

6. In combustion between two shocks motion is rectilinear.
a) True
b) False
Answer: a
Clarification: In combustion between two shocks motion is rectilinear.

7. Euken number is introduced in _______ atomic gases.
a) mono
b) poly
c) di
d) none of the mentioned
Answer: b
Clarification: Euken number is introduced in poly atomic gases and mono atomic gases also.

8. For mono atomic gases euken number is approximately _________
a) 5
b) 3
c) 4
d) 2.5
Answer: d
Clarification: For mono atomic gases euken number is approximately 2.5

9. Inter changeability of gases gives _________
a) wobbe index
b) euken number
c) wobbe index & euken number
d) none of the mentioned
Answer: a
Clarification: Wobbe index gives interchangeability of gases during combustion.

10. Methane number is used to define auto ignition.
a) True
b) False
Answer:a
Clarification: Methane number is used to define auto ignition.

Steam and Gas Turbines Multiple Choice Questions on “Usage of Gas Turbines in Jet Engines”.

1. Jet engines are classified into _______ types.
a) 5
b) 4
c) 3
d) 2
Answer: a
Clarification: Jet engines are classified into five types. They are
Turboshafts
Turbo jets
Turbo props
Turbofans
Propfan.

2. Jet engines works on ______ cycle.
a) brayton
b) dual
c) dual
d) otto
Answer: d
Clarification: Jet engines works on brayton cycle. Gasoline engines works on the otto cycle.

3. __________ bypass turbo fan engines are used in sub sonic flights.
a) Medium
b) Low
c) High
d) None of the mentioned
Answer: c
Clarification: High bypass turbo fan engines are used in sub sonic flights. High bypass turbo fan engines produce more power output.

4. Jet engines works from newton’s law of motion.
a) True
b) False
Answer: a
Clarification: Jet engines works from newton’s law of motion.

5. Turbofans gives more efficiency when the speed is ______ than the mach speed.
a) greater
b) less
c) equal
d) none of the mentioned
Answer: b
Clarification: Turbofans efficiency decreases when the speed exceeds the mach number.

6. _________ compressors are used in turbojets.
a) Axial
b) Radial
c) Axial & Radial
d) None of the mentioned
Answer: a
Clarification: Turbojets use axial or centrifugal compressors. Centrifugal compressors pressurizes the working fluid by centrifugal principle.

7. ____________ compressors can be used in turbojets.
a) Radial
b) Centrifugal
c) Radial & Centrifugal
d) None of the mentioned
Answer: b
Clarification: Both centrifugal or axial compressors can be used in turbo jets.

8. Internal energy in the fuel is converted into __________ of the exhaust in turbojets.
a) kinetic energy
b) pressure energy
c) kinetic & pressure energy
d) none of the mentioned
Answer: a
Clarification: Internal energy in the fuel is converted into kinetic energy of the exhaust in turbojets. Compressors convert internal energy of the fluid into velocity and hence kinetic energy is increased.

9. Gas generator core is used in turbo fans.
a) True
b) False
Answer: a
Clarification: Gas generator cores are used to convert internal energy of the gas to kinetic energy of the exhaust.

10. Jet engines have ________ shafts.
a) single
b) multiple
c) single or multiple
d) none of the mentioned
Answer: c
Clarification: Jet engines may have multiple shafts depending on their energy requirements.

Automobile Engineering Multiple Choice Questions on “Transmission System – Clutches”.

1. If there are 7 clutch plates in a multi-plate clutch, what is the number of pair of contact surfaces?
a) 5
b) 4
c) 6
d) 8
Answer: c
Clarification: If ‘n’ is the no. of clutch plates in a multi-plate clutch, then, number of pairs of contact surfaces = ‘n-1’. Therefore no. clutches plates = 7 – 1 = 6.

2. External diameter of the clutch facing is limited to 120 mm and the inner diameter may be assumed to be 0.3 times the external diameter. Assume uniform wear theory. What is the effective mean radius?
a) 68
b) 58
c) 98
d) 78
Answer: d
Clarification: External diameter = 120 mm. Given Internal diameter = 0.3*external diameter = 0.3 * 120 = 36 mm. Effective mean diameter = (120 + 36) / 2 = 78 mm ⇒ Effective mean radius = 39 mm.

3. The clutch plate has 160 mm inside and 240 mm outside diameter. The total force provided by the springs is 5 kN, when the clutch is new. The coefficient of friction is 0.4. What is the torque transmitted?
a) 300 Nm
b) 350 Nm
c) 400 Nm
d) 450 Nm
Answer: c
Clarification: inside radius = 80 mm, outside radius = 120 mm ⇒ Effective mean radius = R = (80 + 120) / 2 = 100 mm. Let W = 5 kN = 5000 N and μ = coefficient of friction = 0.4. Torque transmitted = 2 * μ * W * R = 2 * 0.4 * 5000 * 100 = 400 * 10³ Nmm = 400 Nm.

4. Which of the following contains no linkage between the clutch and the pedal?
a) Clutch – by – wire
b) Wet clutch
c) Hydraulic single plate clutch
d) Hydraulic multi-plate clutch
Answer: a
Clarification: In clutch – by – wire system, there is no mechanical linkage between the clutch and the pedal. The ECU and the actuator control the clutch pedal.

5. Where is the clutch located?
a) Between transmission and engine
b) Between transmission and rear axle
c) Between transmission and propeller shaft
d) Between transmission and differential
Answer: a
Clarification: The clutch is in the middle of transmission and engine. So that torque can be transmitted from engine to the transmission whenever required.

6. Which of the following parts of the cover assembly that hold the pressure plate against the clutch plate?
a) Springs
b) Thrust bearings
c) Struts
d) Lever
Answer: a
Clarification: Springs hold the pressure plate against the clutch plate so that pressure can be exerted against the clutch plate and better power transmission can be obtained.

7. Which of the following is the coefficient of friction of the clutch plate?
a) 1.3
b) 0.8
c) 0.4
d) 0.1
Answer: c
Clarification: The coefficient of friction is always less than 1. Most commonly used material for the clutch plate is ceramic in case of racing cars, heavy loads, etc.

8. Which of the following is the disadvantage of the cone clutch?
a) It becomes difficult to disengage the clutch when the cone angle is less than 20°
b) It is silent in operation
c) The normal force on the contact surface is larger than the axial force
d) Same torque can be transmitted for the same size as the plate clutch
Answer: a
Clarification: When the cone angle of the cone clutch is less than 20° than the male part of the clutch join the female part and it difficult to disengage the clutch.

9. The external radius of the cone clutch is 120 mm and the internal radius is 80 mm. The cone angle is kept at 20°. What is the effective mean radius assuming the uniform wear theory?
a) 292 mm
b) 295 mm
c) 100 mm
d) 150 mm
Answer: a
Clarification: r_i = 80 mm, r₀ = 120 mm and θ = 20°. Effective mean radius = (r_i + r_o) / (2*Sin(θ)) = (80 + 120) / (2 * Sin(20°)) = 292.3 mm.

10. The dry clutch can tolerate longer engagement time than a wet clutch.
a) True
b) False
Answer: b
Clarification: Since metal to oil heat transfer is more effective than the metal to the air, the wet clutch acts as a much better heat exchanger and wet clutch can tolerate longer engagement time.

Steam and Gas Turbines Multiple Choice Questions on “Carnot, Rankine and Reheat cycle”.

1. Carnot engine follows ____________
a) Isothermal process
b) Isoentropic process
c) Isothermal and Isoentropic process
d) None of the mentioned
Answer: c
Clarification: Carnot cycle process follows 4 process. They are
Isothermal heat addition
Reversible adiabatic expansion
Reversible isothermal compression
Reversible adiabatic heat rejection.

2. Clausius inequality is applied at _____________
a) reversible isothermal heat addition
b) reversible adiabatic expansion
c) reversible isothermal compression
d) reversible isothermal heat rejection
Answer: c
Clarification: In reversible adiabatic compression entropy is same as from reversible isothermal heat addition and this can be found out by clausius inequality.

3. During reversible adiabatic explansion and compression entropy doesnot change.
a) True
b) False
Answer: a
Clarification: Adiabatic process mean there is no heat transfer and if there is no heat transfer entropy doesnot change.

4. What happens if all the process in carnot cycle be reversed?
a) Works as heat engine
b) PMM1 occurs
c) Works as refrigerator
d) PMM2 occurs
Answer: c
Clarification: When all the process in carnot cycle be reversed heat is absorbed from the body and reduces the temperature of the body which means a refrigerator. When carnot cycle is not reversed it acts as a heat engine.

5. Working fluid of rankine cycle usually _____________
a) Water
b) Methane
c) Hard water
d) None of the mentioned
Answer: a
Clarification: Water is used as working fluid in rankine cycle.

6. Steam turbines work on __________
a) Rankine cycle
b) Carnot cycle
c) Dual cycle
d) None of the mentioned
Answer: a
Clarification: Rankine cycle is generally used where heat energy is to be converted in mechanical energy.

7. In non ideal rankine cycle the compression of pump and expansion of turbine is isoentropic.
a) True
b) False
Answer: b
Clarification: In general isoentropic cases are harder to occur and hence in rankine cycle they doesnot exist as isoentropic process.

8. What is the use of reheat cycle in steam turbines?
a) To remove the moisture from the steam
b) To increase the steam temperature
c) To increase steam pressure
d) None of the mentioned
Answer: a
Clarification: Reheat cycle is worked with rankine cycle to remove the moisture from the steam.

9. In rankine cycle with reheat how mny turbines work?
a) 1
b) 2
c) 3
d) 4
Answer: b
Clarification: One turbine is to produce work and the other turbine is to reheat.

10. Reheat temperatures are very close to ______ temperature.
a) inlet
b) outlet
c) intermediate
d) none of the mentioned
Answer: a
Clarification: After passing from the first turbine again the steam enters the boiler to raise their temperature close to the inlet temperature and then enters the low pressure turbine.

Steam and Gas Turbines Multiple Choice Questions on ” Design of Turbine Flow Passages”.

1. A turbine having alternate blades and nozzles is called as _______________
a) Impulse turbine
b) Reaction turbine
c) Impulse & Reaction turbine
d) None of the mentioned
Answer: a
Clarification: When blades and nozzles are arranged in alternate manner pressure loss can be reduced and hence it is called an impulse turbine.

2. Multi stage arrangement of turbines is called as __________
a) Impulse turbine
b) Reaction turbine
c) Compounding
d) None of the mentioned
Answer: c
Clarification: Multi stage arrangement of turbines reduces the pressure loss and velocity losses and hence it is called as compounding.

3. Compounding __________ efficiency at low speed.
a) decrease
b) increase
c) maximizes
d) none of the mentioned
Answer: b
Clarification: Even at low speeds velocity wastage is prevented and hence efficiency is increased.

4. In pressure compounded turbines moving nozzles are followed by turbine blades.
a) True
b) False
Answer: b
Clarification: In pressure compounding fixed nozzles are followed by moving blades.

5. In pressure compounded turbines flow passage is from ______________
a) moving nozzles to fixed blades
b) fixed nozzles to moving blades
c) fixed blades to moving nozzles
d) none of the mentioned
Answer: b
Clarification: In pressure compounded turbines pressure drop is reduced into stages reducing the pressure loss and hence increasing the efficiency. Hence in pressure compounded turbines flow passage if from fixed nozzles to moving blades.

6. In velocity compounded turbines flow passage is from ____________
a) moving blades to fixed nozzles
b) fixed nozzles to moving blades
c) fixed blades to moving nozzles
d) none of the mentioned
Answer: d
Clarification: In velocity compounded turbines velocity drop is maintained in stages and hence reducing velocity loses. Hence in velocity compounded turbines flow passage is from fixed nozzles to multiple rows of moving blades alternating with fixed blades.

7. A velocity compounded impulse turbine is also called as __________
a) Curtis wheel
b) Pressure compounded
c) Curtis wheel & Pressure compounded
d) None of the mentioned
Answer: a
Clarification: Velocity compounded turbines are invented by a scientist called Curtis and hence it is named after his name.

8. Reaction turbine is also called as _________
a) Impulse turbine
b) Curtis wheel
c) Parsons turbine
d) None of the mentioned
Answer: c
Clarification: Reaction turbine was invented by a scientist names Parson and hence it was named after his name.

9. A turbine comprising of fixed blades and moving nozzles is called as reaction turbines.
a) True
b) False
Answer: a
Clarification: In reaction turbines the reaction produced when steam hits the turbine is also utilized to produce power output.

10. Compounding is used for _________ power applications.
a) low
b) high
c) medium
d) none of the mentioned
Answer: b
Clarification: In compounding high powers are produced at low speeds also. Hence for low power production compounding need not be used.