PrepBharat

1. What is Ignition lag?
a) the time taken by fuel after injection to reach upto auto-ignition temperature
b) time before actual fuel injection and the pump plunger starts to pump fuel
c) time corresponding to actual injection and top dead center
d) none of the mentioned

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2. The delay period in petrol engine is of the order of ___________
a) 0.001 sec
b) 0.002 sec
c) 0.01 sec
d) 0.1 sec

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3. Detonation is caused by which of the following unstable compounds?
a) peroxides, aldehydes, and ketones
b) peroxides, aldehydes, oxides, and sulphides
c) aldehydes, oxides, and ketones
d) none of the mentioned

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4. In order to prevent knock in the S.I. engines, the charge away from the spark plug should have ___________
a) low temperature
b) low density
c) rich mixture
d) all of the mentioned

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5. To reduce the possibility of knock in C.I. engines, the first elements of fuel and air should have ___________
a) high temperature
b) high density
c) short delay
d) all of the mentioned

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6. The detonation tendency in petrol engines for specified conditions of fuel rating, compression ratio, speed, etc, can be controlled by having ___________
a) smaller cylinder bore
b) bigger cylinder bore
c) medium cylinder bore
d) none of the mentioned

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7. A fuel will detonate less if it has ___________
a) higher self ignition temperature
b) lower self ignition temperature
c) proper self ignition temperature
d) none of the mentioned

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8. Ignition quality of diesel fuel oil is expressed by an index called ___________
a) octane number
b) cetane number
c) calorific value
d) none of the mentioned

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9. For best results of efficient combustion, high speed diesel engines need an approximate cetane number of _____________
a) 100
b) 10
c) 50
d) 5

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10. Calorific value of diesel oil is of the order of ___________
a) 3000 kcal/kg
b) 5000 kcal/kg
c) 7500 kcal/kg
d) 10000 kcal/kg

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