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This set of Heat Engines Multiple Choice Questions & Answers (MCQs) focuses on Heat Engines Set 15

Q1 | Change in internal energy is least during
  • 25 to 30
  • Constant pressure process
  • Constant volume process
  • Adiabatic process
  • Isothermal process
Q2 | Which of the following is not a petroleum product?
  • Methylated spirit
  • Lubricating oil
  • Kerosene
  • Carbon dioxide
  • Petrol
Q3 | Thermal efficiency of a standard Otto cycle for a compression ratio 5.5, will be
  • 100%
  • 47.50%
  • 20%
  • 35.40%
  • 50%
Q4 | The calorific value of methane can be determined by
  • Bomb calorimeter
  • Bunsen's calorimeter
  • Orsat's apparatus
  • Exhaust gas calorimeter
  • None of the above
Q5 | The fact that the product of pressure and volume of a fixed amount of gas is approximately a constant value is known as
  • Charle's law
  • Gay Lusac's law
  • Dalton's law
  • Lewis law
  • None of the above
Q6 | Air fuel ratio for a jet engine is of the order of
  • 60;1
  • 15;1
  • 600;1
  • 20;1
  • 10;1
Q7 | A steam nozzle is said to be choked when
  • Pressure at throat is equal to steam supply pressure
  • Throat gets clogged
  • Flow is at maximum value of critical exit pressure
  • Steam flow through nozzle ceases
  • Pressure at throat is less than the exit pressure
Q8 | In a four stroke cycle the minimum temperature inside the engine cylinder occurs
  • At the end of exhaust stroke
  • At the end of suction stroke
  • At the end of compression stroke
  • At the beginning of exhaust stroke
  • At the beginning of suction stroke
Q9 | According to Charle's law
  • At constant pressure the volume of a gas is proportional to its absolute temperature
  • At constant temperature, pressure is proportional to temperature
  • At constant temperature, pressure of a gas is proportional to its volume
  • At constant volume the absolute pressure is proportional to the temperature
  • None of the above
Q10 | Prony brakes are used for testing
  • Slow speed engines
  • High speed engines
  • Engines with small flywheel
  • Small engines
  • Large capacity engines
Q11 | In wet dry lubrication of diesel engines
  • Oil is splashed
  • Oil is splashed and pumped to various points
  • Oil is pumped to various points
  • All of the above
  • None of the above
Q12 | In a velocity compounded impulse turbine, while steam flows through the second row of moving blades
  • The velocity increases
  • The velocity reduces
  • Both velocity as well as pressure increase
  • The velocity remains constant
  • The pressure remains constant
Q13 | Ignition accelerators are often used for
  • Diesel engine fuels
  • Petrol engine fuels
  • Gas turbine fuels
  • Gas generators
  • All of the above
Q14 | Which one of the following statements is incorrect
  • Combustion is the processes of heat liberation
  • Combustion is a chemical reaction
  • Combustion is rapid oxidation
  • All of the above
  • None of the above
Q15 | During idling in a compression ignition engine the air fuel ratio may be of the order of
  • 5
  • 20
  • 10
  • 15
  • 30
Q16 | Solid injection in diesel engines implies
  • Use of solid fuels
  • Supply of fuel in the form of solid
  • Injecting fuel with lubricating oil
  • Injecting fuel and air simultaneously
  • Injecting fuel without air
Q17 | Which fuel has maximum resistance to detonation
  • Alcohol
  • n-Heptane
  • Toulene
  • Iso-octane
  • Benzene
Q18 | The level of oil in engine cylinder should be checked when the engine is
  • Not running
  • Running
  • During starting
  • During cranking
  • None of the above
Q19 | The molecular weight of a mixture containing 20% oxygen, 20 percent nitrogen and 60 percent carbon dioxise on volume bases will be nearly
  • 38.4
  • Carbon dioxide
  • 41.4
  • 29.9
  • 33.3
Q20 | Dissociation is
  • Process of heat liberation in which no flame exist
  • Same is combustion
  • Combustion without heat
  • Slow combustion
  • Smokeless combustion
Q21 | Thermodynamic processes are those
  • Where a difference is observed in any macroscopic property of the system between different times or state
  • Where a difference is observed in any microscopic property of the system between different times or state
  • Which occurs in the direction of an intensive property or driving force contained within the system
  • Which require an agency outside the system to force the process
  • None of the above
Q22 | A Lungistrom turbine is a
  • Radial flow reaction turbine
  • Axial flow reaction turbine
  • Radial flow impulse turbine
  • Mixed flow impulse turbine
  • None of the above
Q23 | Highest useful compression ratio is the compression ratio at which
  • An engine can be safely operated
  • An engine gives maximum thermal efficiency
  • An engine operates smoothly
  • Detonation first becomes audible
  • None of the above
Q24 | The pour point of diesel fuel oil must be
  • More than the coldest atmospheric temperature at which oil is to be pumped
  • Less than 0?C
  • Less than the coldest atmospheric temperature of which oil is to be pumped
  • More than 100?C
  • More than 0?C
Q25 | The emission of carbon monoxide in automobile exhaust will be low when the vehicle is
  • Cruising at low speeds
  • Idling
  • Decelerating
  • Cruising at high speeds
  • Accelerating