Engine pistons ‘are usually made of aluminium alloy because it_________________?

Related Mcqs:

1. The pistons are usually given a coating such as tin plating in order to________________?

   A. reduce weight
   B. conduct heat efficiently
   C. reduce possibility of scoring
   D. reduce friction
   E. increase lubrication effect

2. A diesel engine as compared to petrol engine (both running ar rated load) is ____________________?

   A. more efficient
   B. less efficient
   C. equally efficient
   D. unperdictable
   E. other factors will decide it

3. Diesel engine can work on very lean air fuel ratio of the order of 30 : 1. A petrol engine can also work on such a lean ratio provided__________________?

   A. it is properly designed
   B. best quality fuel is used
   C. can not work as it is impossible
   D. flywheel size is proper
   E. engine cooling is stopped

4. The output of a diesel engine can be increased without increasing the engine revolution or size in following way_________________?

   A. feeding more fuel
   B. increasing flywheel size
   C. heating incoming air
   D. scavenging
   E. supercharging

5. The thermal efficiency of a petrol engine of two stroke with crank case scavenging as compared to four stroke petrol engine with same comperssion ratio will be_____________________?

   A. higher
   B. lower
   C. same
   D. depends on size of engine
   E. unpredictable.

6. The ratio of useful power; engine friction exhaust gas losses; cooling water, air and oil losses for a diesel engine is of the order of____________________?

   A. 5:25:30:50
   B. 25:35:5:35
   C. 25:5:10:60
   D. 40:30:15:15
   E. 25:5:35:35

7. The thermal efficiency of a two cycle engine as compared to four cycle engine is_________________?

   A. more
   B. less
   C. same
   D. more upto some load and then less
   E. it may be less or more depending on several other factors

8. For same power and same speed, the flywheel of a four stroke engine as compared to two-stroke I.C. engine will be________________?

   A. smaller
   B. bigger
   C. same size
   D. dependent on other engine parameters
   E. unpredictable

9. For the same size and weight, a two stroke engine as compared to four stroke engine will generate power_________________?

   A. about twice
   B. about 0.5 times
   C. nearly equal
   D. about 1.7 times
   E. about 5 times

10. Scavenging air is supplied to a two-stroke engine at a density greater than that of atmosphere. This means the engine is__________________?

    A. Supercharged
    B. Not supercharged
    C. Charged
    D. Supercharged provided its speed is low