Questions and answers for exam Preparation

MCQs

Total Questions : 347 | Page 4 of 35 pages

Question 31. The relative efficiency of an I.C. engine is the ratio of the indicated thermal efficiency to the air standard efficiency.

Correct
Incorrect
Can't say
None of these

Discuss Question

Answer: Option A. -> Correct
Answer: (a).Correct

Question 32. In diesel engines, the ignition takes place due to the heat produced in the engine cylinder at the end of compression.

Correct
Incorrect
Can't say
None of these

Discuss Question

Answer: Option A. -> Correct
Answer: (a).Correct

Question 33. The volumetric efficiency ofa well designed engine may be

30 to 40%
40 to 60%
60 to 70%
75 to 90%

Discuss Question

Answer: Option D. -> 75 to 90%
Answer: (d).75 to 90%

Question 34. The fuels in order of decreasing knock tendency for spark ignition engines are

paraffins, aromatics, napthenes
paraffins, napthenes, aromatics
napthenes, aromatics, paraffins
napthenes, paraffins, aromatics

Discuss Question

Answer: Option B. -> paraffins, napthenes, aromatics
Answer: (b).paraffins, napthenes, aromatics

Question 35. Which of the following statement is correct regarding the features of a Breeder reactor?

It produces more fuel than it consumes.
It requires highly enriched fuel.
It requires liquid sodium metal as moderator.
all of the above

Discuss Question

Answer: Option D. -> all of the above
Answer: (d).all of the above

Question 36. Plutonium (Pu239) is produced

artificially
by fission of Th232
when U238 is irradiated by neutrons
as basic raw material

Discuss Question

Answer: Option C. -> when U238 is irradiated by neutrons
Answer: (c).when U238 is irradiated by neutrons

Question 37. A petrol engine has compression ratio from

6 to 10
10 to 15
15 to 25
25 to 40

Discuss Question

Answer: Option A. -> 6 to 10
Answer: (a).6 to 10

Question 38. The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called

mechanical efficiency
overall efficiency
indicated thermal efficiency
volumetric efficiency

Discuss Question

Answer: Option B. -> overall efficiency
Answer: (b).overall efficiency

Question 39. Detonation is harmful due to

increase in the rate of heat transfer, there is a reduction in the power output and efficiency of the engine
excessive turbulence which removes most of the insulating gas boundary layer from the cylinder walls
high intensity of knock causes crankshaft vibration and the engine runs rough
none of the above

Discuss Question

Answer: Option D. -> none of the above
Answer: (d).none of the above

Question 40. The brake power (B.P.) of the engine is given by (where W = Brake load or dead load in newtons, l = Length of arm in metres, N = Speed of engine in r.p.m., S - Spring balance reading in newtons, D = Dia. of brake drum in metres, and d = Dia. of rope in metres)