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This set of Heat Engines Multiple Choice Questions & Answers (MCQs) focuses on Heat Engines Set 1
Q1 | Octane number of petrol generally available is in the range
- 10 to 25
- 55 to 65
- 25 to 60
- 20 to 75
- 80 to 100
Q2 | In spark ignition engines, the knocking tendency is reduced by
- Reduction of compression ratio
- Advancing ignition timing
- Increasing exhaust temperature
- Adding dope like tetra ethy lead to the fuel
- All of the above
Q3 | In thermodynamic analysis, a pure substance is that which
- consists of only a single chemical species
- May have a number of chemical species that the composition remains constant
- has no dissolved impurities
- behaves as perfect gas
- None of the above
Q4 | Leaking radiator tubes are generally
- Soldered
- Welded
- Left unattended
- Brazed
- Replaced
Q5 | When steam expands without doing mechanical work, its enthalpy
- Increases
- Decreases
- Does not change
- Depends on the factors
- None of the above
Q6 | Generally steam turbines in power station operate at
- 1000 RPM
- 3000 RPM
- 375 RPM
- 50 RPM
- 1500 RPM
Q7 | Thermionic converters are based on
- Seebeck effect
- Microwave theory
- Energy contained in thermal conductors
- Transfer of electrons
- None of the above
Q8 | Anthydrous substance is
- Dry substance
- Free of hydrogen
- Free of humidity
- Crystalline substance
- Free of water specially water of crystallization
Q9 | Fuel which detonates easily is
- Toulene
- Alcohol
- Iso-octane
- n-Heptane
- Benzene
Q10 | In compression ignition engine fuel ignition accelerators are added to
- Reduce combustion knock
- Accelerate combustion knock
- Reduce combustion chamber temp
- Increase delay period
- None of the above
Q11 | Working pressure of a boiler does not depend upon
- Factor of safety
- Tensile strength of shell
- Thickness of shell
- Efficiency of joint
- Type of fuel being fired
Q12 | Oil rings are slotted to
- Remove oil from cylinder
- Minimise friction
- Reduce the bulk
- Better lubrication of cylinder walls
- Provide an escape for the oil that the slot edges cut from the cylinder wall
Q13 | A gas turbine cycle operates through pressures ratio of 5. Air enters the compressor at atmospheric pressure and 25?C and entry to the turbine is at 800?C. The thermal efficiency of the plant has been found to be 37%. Now, if compressor and turbine efficiencies of 80% are taken into account, the value, of thermal efficiency will be
- 37%
- 40%
- 38.50%
- 17.75%
- 45%
Q14 | The chemical usually added for increasing the knock resistance of a petrol engine is
- Tetra-ethy lead
- n-heptane
- Pyro gallic acid
- Methyl alcohol
- Benzol
Q15 | Pure cetane
- Has cetane number of 0
- Promotes detonation
- Is a straight chain paraffin
- Has cetane number of 100
- Is a blue coloured liquid
Q16 | In aircraft using gas turbine the cycle used is
- Reheating
- Regeneration
- Reheating with regeneration
- Simple
- Multi-stage expansion with reheating and regeneration
Q17 | Which of the following automobile is relatively free from pollution problems
- Diesel engine powered
- Wankel engine powered
- Batterly powered
- Gas turbine powered
- Petrol engine powered
Q18 | During idling a petrol engine requires
- Rich mixture
- None of above
- Chemically correct mixture
- Variable mixture
- Lean mixture
Q19 | A diesel engine is to be redesigned to improve the overload capacity. The design feature which will be influenced is
- Size of fuel injection equipment
- Lubrication
- Air capacity of cylinder
- Cooling water velocity
- All of the above
Q20 | Which of the following pollutants result from automobile exhaust?
- Carbon monoxide
- Nitrous oxide
- Hydro carbons
- Sulphur dioxide
- All of the above
Q21 | Which is incorrect?
- Compression ratio = initial volume + final volume
- Final pressure = Initial pressure x compression ratio
- Initial pressure = final pressure + compression ratio
- Initial volume = compression ratio x final volume
- None of the above
Q22 | Coking is
- Formation of lumps or masses of coke in boiler furnaces at high temperatures
- Heating of coal in absence of air driving carbon and leaving behind the residue of carbon
- Burning of coal in a furnace
- Producing lumps of coal from fine powders with the help of a binder
- None of the above
Q23 | In a diesel engine the inlet pressure is more than the atmospheric pressure. Therefore; it can be concluded that
- The engine is high speed type
- The engine is air cooled
- The engine is water cooled
- The engine is slow speed type
- The engine is supercharged
Q24 | In a impulse turbine while steam flows through the moving blades
- Velocity increases
- Velocity reduces
- Both velocity as well as pressure increase
- Velocity reduces while pressure increases
- Pressure reduces
Q25 | A hydrograph is a plot of discharge through a river versus
- Time
- Velocity of water
- Rate of flow of water
- None of the above
- None of the above