253. Higher calorific value of a fuel is based on the assumption that
A.No water is present in fuel
B.The effect of water present is ignored
C.The water is present in vapor form
D.The water is present in form of small droplets

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254. When an engine is idling, it requires
A.No fuel in the air
B.Lean fuel air mixture
C.Rich fuel air mixture
D.Stoichiometric mixture

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255. An ignition coil in the spark engine performs the function of
A.Controlling spark
B.Controlling current produced by the generator
C.Supplying high voltage to the spark plug
D.Regulating battery voltage

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256. If the gear ratio of first gear and of differential be 1 : 4.5 and 1 : 4 respectively, then the ratio of engine speed and axle speed for the automobile in first gear is
A.1 : 4.5
B.1 : 4
C.1 : 18
D.18 : 1

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257. In the case of compound engine, equal power is developed by each cylinder with a view to
A.Have maximum efficiency
B.Have maximum fuel economy
C.Have interchangeable parts
D.Obtain uniform turning moment

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258. The power to weight ratio of multi cylinder engines with increase in number of cylinders for the same power will
A.Increase
B.Decrease
C.Remain more or less same
D.Depends upon power to be developed

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259. The compression ratio is kept low in petrol engine compared to a diesel because
A.Petrol engine is a light engine
B.It provides fuel economy
C.Faster operation is required in petrol engine
D.Higher compression ratio in pertol engine would lead to pre-ignition of fuel

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