411. The knocking in diesel engines for given fuel, will be__________________?
A. enhanced by increasing compression ratio
B. enhanced by decreasing compression ratio
C. unaflected by compression ratio
D. first enhanced by increasig compression ratio upto a limit beyond which it will be suppressed
E. dependent on other factors

412. According to Recardo’s theory, detonation occurs due to______________________?
A. instantaneous auto-ignition of last part of charge to be burnt
B. improper mixing of air and fuel
C. improper combustion
D. self ignition temperature has nothing to do with detonation
E. none of the above

413. The ignition of charge by some hot surface in the engine cylinder before operation of spark plug is known as________________?
A. auto ignition
B. preignition
C. retarded ignition
D. accelerated ignition
E. detonation

414. Ignition quality of diesel-fuel oil is expressed by an index called__________________?
A. octane number
B. cetane number
C. calorific value
D. carbon content
E. ignition temperature

415. The compression ratio of motor cars is___________________?
A. 5
B. 7
C. 10
D. 13
E. 16

416. Freezing temperature of petrol is usually__________________?
A. 0°C
B. – 10°C
C. 10°C
D. less than – 30°C
E. less than – 273°C

417. The most popular firing order in case of four cylinder in-line I.C. engine is__________________?
A. 1-2-3-4
B. 1-3-2-4
C. 1-4-2-3
D. 1-2-4-3
E. 1-3-4-

418. The specific gravity of diesel oil Is_________________?
A. 1
B. 0.7
C. 0.85
D. 0.5
E. 1.25

419. Detonation can be controlled by_____________________?
A. varying compression ratio
B. using lian mixture
C. retarding the spark timing
D. reducing the r.p.m.
E. increasing inlet pressure

420. The m.e.p. of a diesel cycle having fixed compression ratio with increase in cut-off will_________________?
A. increase
B. decreae
C. be unaffected
D. depend on other factors
E. unpredictable

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