Q.1

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

  • Correct
  • Incorrect
Q.2

In petrol engines, using a fixed octane rating fuel, the increase in engine speed will decrease the knocking tendency.

  • Yes
  • No
Q.3

A long delay period in compression ignition engines gives a more rapid rise in pressure which causes knocking.

  • Yes
  • No
Q.4

The octane number of petrol, generally available, is

  • 20 to 40
  • 40 to 60
  • 60 to 80
  • 80 to 100
Q.5

The air-fuel ratio of the petrol engine is controlled by

  • carburettor
  • injector
  • governor
  • none of these
Q.6

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
Q.7

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
Q.8

A diesel engine has inlet valve, fuel injection valve and exhaust valve.

  • Yes
  • No
Q.9

Materials which make good moderators do not make good reflectors.

  • Correct
  • Incorrect
Q.10

A fission chain reaction in uranium can be developed

  • by increasing the contents of U235
  • by slowing down fast neutrons so that U235 fission continues by slow neutron
  • both (a) and (b)
  • none of these
Q.11

The brake power is the power available

  • in the engine cylinder
  • at the crank shaft
  • at the crank pin
  • none of these
Q.12

If the compression ratio in I.C. engine increases, then its thermal efficiency will

  • decrease
  • increase
  • remain same
Q.13

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
Q.14

In a four stroke cycle diesel engine, the compression

  • starts at 40° after bottom dead centre and ends at 10° before top dead centre
  • starts at 40° before top dead centre and ends at 40° after top dead centre
  • starts at top dead centre and ends at 40° before bottom dead centre
  • may start and end anywhere
Q.15

The ignition of the charge by some hot surface within the engine before the passage of spark is called

  • pre-ignition
  • detonation
  • ignition delay
  • auto-ignition
Q.16

Thermal efficiency of a two stroke cycle engine is __________ a four stroke cycle engine.

  • equal to
  • less than
  • greater than
Q.17

The slowing down of fast neutrons is desirable because slow moving neutrons are more effective than fast neutrons in triggering fission.

  • Agree
  • Disagree
Q.18

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

  • Correct
  • Incorrect
Q.19

Plutonium (Pu239) is produced

  • artificially
  • by fission of Th232
  • when U238 is irradiated by neutrons
  • as basic raw material
Q.20

A power plant giving least running cost of production of electrical power is

  • steam power plant
  • gas turbine power plant
  • hydro electric power plant
  • nuclear power plant
Q.21

In a four stroke cycle diesel engine, the inlet valve

  • opens at 20° before top dead centre and closes at 40° after bottom dead centre
  • opens at 20° after top dead centre and closes at 20° before bottom dead centre
  • opens at top dead centre and closes at bottom dead centre
  • may open and close anywhere
Q.22

Special reactors, called breeder reactors, supply a net gain of fissionable material.

  • True
  • False
Q.23

A supercharged engine as compared to an ordinary engine

  • is lighter
  • requires smaller foundations
  • consumes less lubricating oil
  • all of these
Q.24

A power plant giving least running cost of production of electrical power is

  • steam power plant
  • gas turbine power plant
  • hydro electric power plant
  • nuclear power plant
Q.25

The normal heptane (C7H16) is given a rating of __________ octane number.

  • 0
  • 50
  • 100
  • 120
Q.26

The volumetric efficiency ofa well designed engine may be

  • 30 to 40%
  • 40 to 60%
  • 60 to 70%
  • 75 to 90%
Q.27

A petrol engine has compression ratio from

  • 6 to 10
  • 10 to 15
  • 15 to 25
  • 25 to 40
Q.28

The thermal efficiency of petrol and gas engines is about

  • 15%
  • 30%
  • 50%
  • 70%
Q.29

The knocking in diesel engines may be prevented by

  • reducing the delay period
  • raising the compression ratio
  • increasing the inlet pressure of air
  • all of these
Q.30

The ratio of the indicated thermal efficiency to the air standard efficiency is known as

  • mechanical efficiency
  • overall efficiency
  • volumetric efficiency
  • relative efficiency
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