Extra Question Yellow Marked Give It In Paper.docx

1. If the temperature of intake air in internal combustion engine increases, then its efficiency will a. Remains same b. Decrease c. Increase d. None of these 2. The operation of forcing additional air under pressure in the engine cylinder is known as a. Scavenging b. Turbulence c. Supercharging d. Pre-ignition 3. The ignition quality of petrol is expressed by a. Cetane no. b. Octane no. c. Calorific value 4. The mean effective pressure obtained from engine indicator indicates the a. Maximum pressure b. Minimum Pressure c. Instantaneous pressure d. Average pressure 5. In a four stroke cycle petrol engine, the compression a. Starts at 40° after bottom dead centre and ends at 30° before top dead centre b. Starts at 40° before bottom dead centre and ends at 30° after bottom dead centre c. Starts at bottom dead centre and ends at top dead centre d. May start and end anywhere 6. Supercharging is the process of a. Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere b. Providing forced cooling air c. Injecting excess fuel for raising more loads d. Supplying compressed air to remove combustion products fully 7. In a four stroke cycle diesel engine, the exhaust valve a. Opens at 30° before bottom dead centre and closes at 10° after top dead centre b. Opens at 30° after bottom dead centre and closes at 10° before top dead centre c. Opens at bottom dead centre and closes at top dead centre d. May open and close anywhere 8. In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is __________ the atmospheric pressure. a. Equal to b. Below c.Above 9. In a petrol engine, if diesel is used, then the engine will a. Run more efficiently b. Run at high speed c. Explode d. Not run 10. Combustion in compression ignition engines is a. Homogeneous b. Heterogeneous c. Both (A) and (B) d. Laminar 11. The colour of exhaust from diesel engine is generally a. White b. Bluish c. Black d. Violet 12. In a four stroke cycle petrol engine, the charge is ignited at a. 30° after top dead center b. 30° before bottom dead center c. 30° after bottom dead center

d. 30° before top dead center 13. The knocking tendency in spark ignition engines may be decreased by a. b. c. d.

Controlling the air-fuel mixture Controlling the ignition timing Controlling the exhaust temperature Reducing the compression ratio 14. The term scavenging is generally associated with a. 2-stroke cycle engines b. 4-stroke cycle engines c. Aeroplane engines d. High efficiency engines 15. The increase in intake temperature of internal combustion engines will _________ efficiency.

a. Increase b. Decrease c. None of these 16. The thermal efficiency of a petrol engine is _________ as compared to diesel engine. a. Same b. Less c. More 17. The ignition quality of diesel oil is expressed by a. b. c. d. 18. a. b. c. d. 19.

Cetane number Octane number Calorific value None of these If petrol is used in a diesel engine, then Low power will be produced Efficiency will be low Higher knocking will occur Black smoke will be produced A diesel engine, during suction stroke, draws

a. b. c. 20. a. b. c. d. 21.

Air only Diesel only A mixture of diesel and air A petrol engine has compression ratio from 6 to 10 10 to 15 15 to 25 25 to 40 The air-fuel ratio of the petrol engine is controlled by

a. b. c. d.

a. b. c. d. 22.

Fuel pump Governor Injector Carburettor In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the

a. b. c. d. 23.

Beginning of suction stroke End of suction stroke Beginning of exhaust stroke End of exhaust stroke The exhaust valve in a four stroke cycle petrol engine

Opens at 50° before bottom dead center and closes at 15° after top dead center Opens at bottom dead center and closes at top dead center Opens at 50° after bottom dead center and closes at 15° before top dead center May open and close anywhere 24. The pressure inside the cylinder is _________ the atmospheric pressure during the exhaust stroke. a. Equal to b. Below c.Above 25. The theoretically correct mixture of air and petrol is a. 10:1 b. 15: 1 c. 18:1