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This set of Heat Engines Multiple Choice Questions & Answers (MCQs) focuses on Heat Engines Set 12
Q1 | Which of the following can have octane rating of more than 100?
- Gobar gas
- Normal petrol
- Methyl alcohol
- Benzol
- Ethyl alcohol
Q2 | Normally the colour of exhaust from a diesel engine is
- Bluish
- Reddish
- Violet
- Black
- Yellowish
Q3 | For initially dry and saturated steam flowing through a nozzle the volue of critical pressure ratio is given by
- 0.577
- 1
- 0.528
- 0.546
- 0.75
Q4 | Which of the following type of internal combustion engines uses rocker arms?
- Radial engines
- Side valve engines
- Overhead valve engines
- Stationary engines
- All of the above
Q5 | In naturally aspirated engine the pressure inside cylinder at the end of suction stroke is
- Less than atmospheric
- Same as atmospheric
- More than atmospheric
- Depends on atmospheric conditions
- None of the above
Q6 | The ash content in diesel oil should not exceed
- 0.10%
- 0.50%
- 5%
- 0.01%
- 1%
Q7 | A hot short metal is
- Brittle when heated
- Brittle when cold
- Ductile at low temperatures
- Ductile at high temperatures
- None of the above
Q8 | In a SI engine the advancing of spark timing will
- Increase knocking tendency
- Reduce knocking tendency
- Not have any effect
- Depends on intensity of spark only
- None of the above
Q9 | Of the calorific value ranges given below which one is generally for coal?
- 2500 - 4000 kcal/kg
- 1000 - 2500 kcal/kg
- 4000 - 7000 kcal/kg
- 8000 - 12000 kcal/kg
- 100 - 1000 kcal/kg
Q10 | The function of a piston rins in an internal combustion engine is
- To prevent lubricating oil from entering the combustion space
- To prevent leakage of combustion chamber products
- To transfer heat from piston to cylinder walls
- All of the above
- None of the above
Q11 | Zeroth law of thermodynamics states that
- Two systems are always in equilibrium
- If two systems are in equilibrium the third system will also be in equilibrium
- If two systems are in thermal equilibrium with a third system, then they are in equilibrium with each other
- Two systems not in equilibrium with a third system are also not in equilibrium with each other
- None of the above
Q12 | For the same peak pressure and heat input
- Otto cycle is more efficient
- Diesel cycle is more efficient
- Both are equally efficient
- None of the above
Q13 | In a jet propulsion unit the products of combustion after passing through the gas turbine are discharged into
- Recycled back to compressor
- Atmosphere
- Compressor
- Vacuum
- Discharge nozzle
Q14 | A D-slide valve is used in
- Two stroke engines
- Diesel engines
- Petrol engines
- Steam engines
- Double acting engines
Q15 | The Clapeyron equation is applicable for
- System in equilibrium
- Change of state
- Change of state when two phases are in equilibrium
- Change of state when water and water vapours are involved
- None of the above
Q16 | Speed drop is the
- Drop in engine speed
- Increasing in engine speed
- Reduction in engine speed from no loads to full load
- Change in engine speed while fuel supply remains the same
- None of the above
Q17 | For reciprocating air compressor the law of compression desired is isothermal and that may be possible by
- Very high speeds
- very low speeds
- any speed as speed does not affect the compression law
- None of the above
- Carbon dioxide
Q18 | In a surface condenser near to the air pump suction the vacuum is 500 mm of mercury with 730 mm of mercury height in a barometer. The pressure near the air pump suction would be
- 0.69 kg/sq-cm
- 1.213 kg/sq-cm
- 0.313 kg/sq-cm
- 0.687 kg/sq-cm
- 1230 mm Hg
Q19 | Which of the following fuel can be obtained by fermentation of vegetable matter?
- Alcohol
- Gasoline
- Benzene
- Carbon dioxide
- Diesel
Q20 | If performance of SI engines of different manufacture having different capacities, sizes and systems are to be compared the common parameter would be
- Engine cylinder diameter
- B.H.P.
- Weight of engine
- Speed
- Mean effective pressure
Q21 | Which of the following is not a part of diesel engine?
- Gudgeon pin
- Air filter
- Oil pump
- Condenser
- Lubricating oil filter
Q22 | Compression ratio for spark ignition engines varies in the range
- 6 to 12
- 20 to 25
- 4 to 6
- 25 to 30
- 12 to 20
Q23 | If a heat engine given an output of 3.5 kW and input is 10000 Joules per second, the thermal efficiency of the engine will be
- 66?%
- 35%
- 30%
- 65%
- 55%
Q24 | Inlet valve of a IC engine remains open for
- 180?
- 250?
- 300?
- 150?
- 280?
Q25 | The capacity of an automobile battery is expressed in terms of
- Number of cells
- Number of plate
- Ampere hours
- Amperes
- Voltage