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- Question
The thermal efficiency of petrol and gas engines is about
Options- A. 15%
- B. 30%
- C. 50%
- D. 70%
- Correct Answer
- 30%
- 1. Plutonium (Pu239) is produced
Options- A. artificially
- B. by fission of Th232
- C. when U238 is irradiated by neutrons
- D. as basic raw material Discuss
- 2. The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called
Options- A. mechanical efficiency
- B. overall efficiency
- C. indicated thermal efficiency
- D. volumetric efficiency Discuss
- 3. In a four stroke cycle diesel engine, the compression
Options- A. starts at 40° after bottom dead centre and ends at 10° before top dead centre
- B. starts at 40° before top dead centre and ends at 40° after top dead centre
- C. starts at top dead centre and ends at 40° before bottom dead centre
- D. may start and end anywhere Discuss
- 4. The air standard efficiency ofan I.C. engine is given by (where r = Compression ratio, and ? = Ratio of specific heats)
Options- A. 1 - r? - 1
- B. 1 + r? - 1
- C.
- D. none of these Discuss
- 5. The octane number of petrol, generally available, is
Options- A. 20 to 40
- B. 40 to 60
- C. 60 to 80
- D. 80 to 100 Discuss
- 6. A fission chain reaction in uranium can be developed
Options- A. by increasing the contents of U235
- B. by slowing down fast neutrons so that U235 fission continues by slow neutron
- C. both (a) and (b)
- D. none of these Discuss
- 7. The normal heptane (C7H16) is given a rating of __________ octane number.
Options- A. 0
- B. 50
- C. 100
- D. 120 Discuss
- 8. The knocking in diesel engines may be prevented by
Options- A. reducing the delay period
- B. raising the compression ratio
- C. increasing the inlet pressure of air
- D. all of these Discuss
- 9. Detonation is harmful due to
Options- A. increase in the rate of heat transfer, there is a reduction in the power output and efficiency of the engine
- B. excessive turbulence which removes most of the insulating gas boundary layer from the cylinder walls
- C. high intensity of knock causes crankshaft vibration and the engine runs rough
- D. none of the above Discuss
- 10. A long delay period in compression ignition engines gives a more rapid rise in pressure which causes knocking.
Options- A. Yes
- B. No Discuss
IC Engines and Nuclear Power Plants problems
Search Results
Correct Answer: when U238 is irradiated by neutrons
Correct Answer: overall efficiency
Correct Answer: starts at 40° after bottom dead centre and ends at 10° before top dead centre
Correct Answer:
Correct Answer: 80 to 100
Correct Answer: both (a) and (b)
Correct Answer: 0
Correct Answer: all of these
Correct Answer: none of the above
Correct Answer: Yes
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