০৩। A diesel engine has inlet valve, fuel injection valve and exhaust valve.
ক) Yes
খ) No
০৪। A diesel engine is __________ as compared to petrol engine, both running at rated load.
ক) equally efficient
খ) less efficient
গ) more efficient
০৫। A diesel engine, during suction stroke, draws
ক) air only
খ) diesel only
গ) a mixture of diesel and air
০৬। A fission chain reaction in uranium can be developed
ক) by increasing the contents of U235
খ) by slowing down fast neutrons so that U235 fission continues by slow neutron
গ) both (a) and (b)
ঘ) none of these
০৭। A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of
ক) 75% iso-octane and 25% normal heptane
খ) 75% normal heptane and 25% iso-octane
গ) 75% petrol and 25% diesel
ঘ) 75% diesel and 25% petrol
০৮। A fuel of cetane number 40 has the same ignition quality as a mixture of
ক) 40% cetane and 60% alpha methyl napthalene
খ) 40% alpha methyl napthalene and 60% cetane
গ) 40% petrol and 60% diesel
ঘ) 40% diesel and 60% petrol
০৯। A fuel will detonate less if it has higher self ignition temperature.
ক) True
খ) False
১০। A gas engine has a swept volume of 300 cm3 and clearance volume of 25 cm3. Its volumetric efficiency is 0.88 and mechanical efficiency is 0.90. The volume of the mixture taken in per stroke is
ক) 248 cm3
খ) 252 cm3
গ) 264 cm3
ঘ) 286 cm3
১১। A higher compression ratio causes
ক) pre-ignition
খ) increase in detonation
গ) an acceleration in the rate of combustion
ঘ) any one of these
১২। A long delay period in compression ignition engines gives a more rapid rise in pressure which causes knocking.
ক) Yes
খ) No
১৩। A mixture containing 65% of iso-octane and 35% of normal heptane will have
ক) cetane number 65
খ) octane number 65
গ) qetane number 35
ঘ) octane number 35
১৪। A moderator
ক) absorbs neutrons
খ) does not absorb neutrons
গ) accelerates neutrons
ঘ) none of these
১৫। A moderator generally used in nuclear power plants is
ক) graphite
খ) heavy water
গ) concrete
ঘ) graphite and concrete
১৬। A moderator, apart from its high neutron slowing power, and low non-productive neutron, should be
ক) stable under nuclear radiation
খ) corrossion resistant
গ) good thermal conductor
ঘ) all of these
১৭। A moderator, in nuclear power plants, is a medium introduced into the fuel mass in order to
ক) slow down the speed of fast moving neutrons
খ) control the reaction
গ) reduce the temperature
ঘ) extract heat from nuclear reaction
১৮। A nuclear power plant differs from a conventional steam power station only in the steam generating part.
ক) Agree
খ) Disagree
১৯। A nuclear reactor is said to be critical when the neutron population in the reactor core is
ক) rapidly increasing leading to the point of explosion