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This set of Heat Engines Multiple Choice Questions & Answers (MCQs) focuses on Heat Engines Set 3

Q1 | A petrol engine as compared to diesel engine (both running at full load) is
  • More efficient
  • Less efficient
  • Equally efficient
  • Depend on other factors
  • None of the above
Q2 | Which one of the following assumptions is not involved while deriving relation for air standard efficiency of Otto cycle?
  • The engine operates at mederate rpm
  • There is always thermal and chemical equilibrium
  • Expansion and compression are adiabatic
  • There is no chemical reaction inside the engine clinder
  • The working fluid is air for which the specific heats are constant
Q3 | Which of the following needs constant cleaning in a diesel engine?
  • Air only
  • Fuel only
  • Air, fuel and lubricating oil
  • Lubricating oil only
  • Air and fuel only
Q4 | Bagasse is
  • Fibrous portion of sugarcane left after extracting the juice
  • A variety of coal
  • A fuel consisting of wood etc
  • Same as biogas
  • A kind of rice straw
Q5 | During regenerative feed heating
  • Part of the steam is generated in turbine
  • Condenser is supplied with dry and staturated steam
  • Part of the steam is bled from turbine for feed water heating
  • High pressure steam is used to heat low pressure steam coming out of the turbine after expansion
  • None of the above
Q6 | A jet engine has
  • Propeller in front
  • Propeller in back
  • No propeller
  • Propeller on the top
  • None of the above
Q7 | Anti-knock for compression ignition engines is
  • Amyl nitrate
  • Aromatics
  • Hexadecane
  • Tetra ethyl lead
  • Trimethyl pentane
Q8 | Which statement is incorrect?
  • LH.P of engines can be determined by more test
  • Morse test can be conducted only on multicylinder engines
  • Morse test can be conducted on petrol engines
  • Morse test can be conducted on CFR engine.
  • Morse test can also be conducted on diesel engines
Q9 | Advantage of a diesel engine over petrol engine is
  • Low fuel consumption at full load as well as part load
  • Smooth operation at all speeds
  • Low compression ratio
  • No detonation problems
  • All of the above
Q10 | Forced circulation of water does not take place in which of the following boiler?
  • Benson boiler
  • La Mont boiler
  • Babcock and Wilcox boiler
  • Lancashire boiler
  • Velox boiler
Q11 | In multistage compression, perfect intercooling means
  • Temperature of air at inlet to subsequent stages is equal to initial temperature
  • Temperature of air at inlet to subsequent stages is less than initial temperature
  • Temperature of air at inlet to subsequent stages should be zero
  • Temperature of inlet to subsequent stages should be equal to the final temperature
  • None of the above
Q12 | The battery used in vespa scooter is
  • No battery is used in the scooters
  • Dry-cell type
  • Lead acid type
  • Nickel-iron type
  • Nickel cadmium type
Q13 | Which variety of coal has low calorific value?
  • Steam coal
  • Bituminous coal
  • Lignite
  • Anthracite
  • None of the above
Q14 | Stoichiometric ratio is
  • Chemically correct air-fuel ratio by volume
  • Chemically correct air-fuel ratio by weight
  • Theoretical mixture of air for complete combustion
  • Actual ratio of air to fuel for maximum efficiency
  • None of the above
Q15 | Hot spots are
  • Defects in S.I.engines
  • Hottest point within engine cylinder
  • Do not exist in engines
  • The spots where heavier fractions of fuel are vaporised
  • The hottest spots in engines
Q16 | Air required for complete combustion of 1 kg of carbon is 11.6 kg. If a fuel contains 88.6% Carbon and 11.4% Hydrogen, the air requirement will
  • Will decrease
  • 12 kg
  • Will increase
  • Remain unaltered
Q17 | Volumetric efficiency of a well designed engine may be in the range
  • 40 to 50 percent
  • 50 to 75 percent
  • 75 to 90 percent
  • Below 40 percent
  • Below 20 percent
Q18 | If the boiler chimney emission consists of dense white smoke, then it can be concluded that
  • Coal contains high percentage of sulphur
  • Insufficient air has been supplied for combustion
  • Chemically correct air has been supplied for combustion
  • Excess air has been supplied for combustion
  • Coal contains high percentage of ash
Q19 | Compression ratio in case of gas engines waries in the range
  • 10 to 15
  • 5 to 10
  • 24 to 30
  • 20 to 24
  • 15 to 20
Q20 | A back pressure generally operates on pressures in the range
  • 150 - 200 kg/cm2
  • 15 - 40 kg/cm2
  • 100 - 150 kg/cm2
  • 50 - 100 kg/cm2
  • 200 - 350 kg/cm2
Q21 | In automobiles as the speed of vehicle increases the back pressure
  • Increases
  • Reduces
  • Remains unaffected
  • Depends on other factors
  • None of the above
Q22 | A mechanical indicator is used to determine
  • Pumping horse power
  • Indicated horse power
  • IHP - BHP
  • Friction horse power
  • Brake horse power
Q23 | During adiabatic compression
  • No heat leaves or enters the system
  • Maximum work is done
  • Specific heat remains constant
  • Temperature remains constant
  • None of the above
Q24 | Safety valve generally used on high pressure boiler is
  • Dead weight type
  • Lever type
  • Combination lever and spring type
  • Spring type
  • None of the above
Q25 | Which of the following engine indicator has least inertia effects?
  • Mechanical indicator
  • Farnborough indicator
  • CRO engine indicator
  • All of the above
  • Carbon dioxide