21. Which of the following does not relate to a compression ignition engine?
A. Fuel pump
B. Fuel injector
C. Governor
D. Carburetor
22. Which of the following statement is correct regarding petrol engines?
A. A fine fuel spray mixed with air is ignited by the heat of compression which is at a high pressure.
B. The fuel supplied to the engine cylinder is mixed with necessary amount of air and the mixture is ignited with the help of a spark plug.
C. The fuel is first evaporated after passing through a carburetor and is mixed with air before ignition.
D. all of the above
23. Supercharging __________ the power developed by the engine.
A. has no effect on
B. increases
C. decreases
24. Uranium has isotopes
A. U234
B. U235
C. U238
D. all of these
25. The color of exhaust from the diesel engine is generally
A. white
B. bluish
C. black
D. violent
26. In compression ignition engines, swirl denotes a
A. haphazard motion of the gases in the chamber
B. rotary motion of the gases in the chamber
C. radial motion of the gases in the chamber
D. none of the above
27. A mixture containing 65% of iso-octane and 35% of normal heptane will have
A. cetane number 65
B. octane number 65
C. qetane number 35
D. octane number 35
28. Which of the following statement is wrong?
A. In compression ignition engines, detonation occurs near the beginning of combustion.
B. Since the fuel, in compression ignition engines, is injected at the end of compression stroke, therefore, there will be no pre-ignition.
C. To eliminate knock in compression ignition engines, we want to achieve auto-ignition not early and desire a long delay period.
D. In compression ignition engines, because of heterogeneous mixture, the rate of pressure rise is comparatively lower.
29. The maximum propulsive efficiency of a turbo-jet engine is at a speed of
A. 1000 km/h
B. 2000 km/h
C. 2400 km/h
D. 3000 km/h
30. In order to mix air and petrol in the required proportion and to supply it to the engine during suction stroke, then __________ is employed.
A. fuel pump
B. injector
C. carburetor
D. none of these