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Multiple choice question for engineering

Set 1

1. The value of the reheat factor varies from
a) 1.08 to 1.10
b) 1.2 to 1.6
c) 1.6 to 2
d) 1.02 to 1.06

View Answer

Answer: d [Reason:] The value of the reheat factor varies from 1.02 to 1.06.

2. The difference of supersaturated temperature and saturation temperature at that pressure is called
a) degree of super saturation
b) degree of superheat
c) degree of undercooling
d) none of the mentioned

View Answer

Answer: c [Reason:] The difference of supersaturated temperature and saturation temperature at that pressure is called degree of undercooling.

3. Parson’s turbine is a
a) simple impulse turbine
b) impulse-reaction turbine
c) simple reaction turbine
d) none of the mentioned

View Answer

Answer: c [Reason:] Parson’s turbine is a simple reaction turbine.

4. In reaction turbines, the axial thrust is due to
a) pressure drop across the rotor
b) change in axial velocity
c) both (a) and (b)
d) none of the mentioned

View Answer

Answer: c [Reason:] In reaction turbines, the axial thrust is due to the pressure drop across the rotor & change in axial velocity.

5. The flow of steam is super-sonic
a) in the convergent portion of the nozzle
b) at the entrance to the nozzle
c) at the throat of the nozzle
d) in the divergent portion of the nozzle

View Answer

Answer: d [Reason:] The flow of steam is super-sonic in the divergent portion of the nozzle.

6. The variation of steam pressure in the nozzle depends upon
a) dryness fraction of steam
b) specific volume of steam
c) velocity of steam
d) all the mentioned

View Answer

Answer: d [Reason:] The variation of steam pressure in the nozzle depends upon dryness fraction of steam, specifically volume of steam & velocity of steam.

7. A binary vapour plant consists of
a) mercury boiler
b) steam turbine
c) steam condenser
d) all of the mentioned

View Answer

Answer: d [Reason:] A binary vapour plant consists of mercury boiler, steam turbine, steam condenser, etc.

8. The steam enters the nozzle at a
a) low pressure and a low velocity
b) high pressure and a low velocity
c) low pressure and a high velocity
d) high pressure and a high velocity

View Answer

Answer: d [Reason:] The steam enters the nozzle at a high pressure & a high velocity to force the maximum volume into the nozzle.

9. In a reaction turbine, when steam flows through the fixed blades,
a) pressure decreases while velocity increases
b) pressure increases while velocity decreases
c) pressure and velocity both increases
d) pressure and velocity both decreases

View Answer

Answer: a [Reason:] In a reaction turbine, when steam flows through the fixed blades, the pressure decreases while velocity increases.

10. The impulse turbine rotor efficiency will have a maximum value of 0.5 cos2 α, where α is the nozzle exit flow angle, if the
a) blades are equiangular
b) blade velocity coefficient is unity
c) blade solidity is 0.65
d) blades are equiangular and frictionless

View Answer

Answer: d [Reason:] The impulse turbine rotor efficiency will have a maximum value of 0.5 cos2 α, where α is the nozzle exit flow angle, if the blades are equiangular & frictionless.

11. Steam turbines are used for
a) electric power generation
b) large marine propulsion
c) direct drive of fans, compressors, pumps
d) all of the mentioned

View Answer

Answer: d [Reason:] Steam turbines are used for various applications which include, electric power generation, large marine propulsion, direct drive of fans, compressors, pumps, etc.

12. Curtis turbine is a
a) pressure compounded turbine
b) velocity compounded turbine
c) simple reaction turbine
d) pressure-velocity compounded turbine

View Answer

Answer: d [Reason:] A type of the pressure-velocity compounded turbine is a Curtis Turbine.

13. Which of the following statement is correct?
a) The expansion of steam in a nozzle follows Rankine cycle
b) The friction in the nozzle increases the dryness fraction of steam
c) The pressure of steam at throat is called critical pressure
d) All of the mentioned

View Answer

Answer: d [Reason:] All the mentioned statements are correct.

14. Parson’s reaction turbine is a __________ reaction turbine.
a) 40%
b) 50%
c) 60%
d) 70%

View Answer

Answer: b [Reason:] Parson’s reaction turbine is a 50% reaction turbine.

15. The diagram efficiency is the ratio of
a) work done on the blades to the energy supplied to the blades
b) energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam
c) work done on the blades per kg of steam to the total energy supplied per stage per kg of steam
d) none of the mentioned

View Answer

Answer: a [Reason:] The diagram efficiency is the ratio of work done on the blades to the energy supplied to the blades.

Set 2

1. In the T-S diagram of a Rankine cycle, the abscissa represents?
a) total entropy of turbine steam
b) partial entropy of turbine steam
c) partial enthalpy of turbine steam
d) none of the mentioned

View Answer

Answer: a [Reason:] The T-S diagram of a Rankine Cycle has total entropy of turbine steam in the abscissa & temperature on the ordinate.

2. After the expansion of throttle steam, why is some steam extracted?
a) so that the total amount of steam in the entire system remains same
b) so that the variation in temperature is constant
c) so that pressure variation is constant
d) so that the total entropy is reduced

View Answer

Answer: d [Reason:] The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

3. The heat given up by the expansion of throttle steam is utilised in?
a) maintaining the heat flow in the system
b) reducing temperature variation in the system
c) heating the feedwater
d) cooling feedwater

View Answer

Answer: c [Reason:] The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

4. “Regenerative feedwater heating by turbine extraction” is often termed as?
a) Electrophoresis of Rankine cycle
b) Sterlinisation of Rankine cycle
c) Carnotization of Rankine cycle
d) None of the mentioned

View Answer

Answer: c [Reason:] In the T-S diagram, the area of the parallelogram representing the cycle output will be equal to the area of the rectangle representing the output of the Carnot cycle. That is why we often term regenerative feedwater heating by turbine extraction as carnotization of rankine cycle.

5. A regenerative feedwater heating cycle with an infinite number of feedwater heaters has efficiency equal to?
a) Brayton cycle
b) Carnot cycle
c) Diesel cycle
d) Otto cycle

View Answer

Answer: b [Reason:] In the T-S diagram, the area of the parallelogram representing the cycle output will be equal to the area of the rectangle representing the output of the Carnot cycle. Thus, the efficiency of a regenerative feedwater heating cycle with an infinite number of feedwater heaters is equal to that of a carnot cycle.

6. In the T-S diagram, the process of heating from condenser to boiler saturation temperature when the number of turbine extraction stages are finite is?
a) Reversible
b) Irreversible
c) Adiabatic
d) None of the mentioned

View Answer

Answer: b [Reason:] When the number of extraction stages are finite, the process is irreversible. On the contrary, when there are infinite extraction stages, the process becomes reversible.

7. For the process of heating from condenser to boiler saturation temperature to be reversible, the number of extraction stages involved in the entire cycle should be?
a) Zero
b) One
c) Infinite
d) Finite

View Answer

Answer: c [Reason:] When the number of extraction stages are finite, the process is irreversible. On the contrary, when there are infinite extraction stages, the process becomes reversible.

8. Which of the processes immediately follows the expansion of throttle steam?
a) heat given up by the steam is added to feedwater
b) heating from condenser to boiler saturation temperature
c) carnotization of rankine cycle
d) none of the mentioned

View Answer

Answer: a [Reason:] The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

9. The output from boiler goes to?
a) Turbine
b) Condenser
c) Pump
d) Economiser

View Answer

Answer: a [Reason:] The sequence of flow is Boiler, Turbine, Condenser, Pump, Economiser.

10. The area of parallelogram in the T-S diagram representing the cycle output is equal to?
a) area of rectangle representing the output of the Carnot cycle
b) area of the triangle representing the output of the Carnot cycle
c) area of the square representing the output of the Carnot cycle
d) none of the mentioned

View Answer

Answer: a [Reason:] From the T-S diagram the area of parallelogram representing the cycle output is equal to the area of rectangle representing the output of the Carnot cycle.

Set 3

1. The atomic weight and atomic number of an element are A and Z respectively. What is the number of neutrons in the atom of that element?
a) Z
b) A
c) A+Z
d) A-Z

View Answer

Answer: d [Reason:] Number of neutrons = Atomic weight – Atomic number.

2. The time required for half of the __________ of a radioactive isotope to decay is called its half-life.
a) neutron
b) electron
c) proton
d) nuclei

View Answer

Answer: d [Reason:] The time required for half of the nuclei of a radioactive isotope to decay is called its half life.

3. Thermal nuclear reactors using enriched uranium as fuel contains a maximum of __________ percent fissile material i.e. U-235.
a) 1
b) 2
c) 3
d) 6

View Answer

Answer: c [Reason:] Thermal nuclear reactors using enriched uranium as fuel contains a maximum of 6 percent fissile material i.e. U-235.

4. __________ moderator is used in a fast breeder reactor.
a) Heavy water
b) Graphite
c) No
d) Beryllium

View Answer

Answer: c [Reason:] A fast breeder reactor doesn’t employ any moderator.

5. Nuclides having the same atomic number are termed as?
a) Isobars
b) Isotones
c) Isotopes
d) Isomers

View Answer

Answer: d [Reason:] Isomers are nuclides having the same atomic number.

6. Main source of __________ is monazite sand
a) Uranium
b) Polonium
c) Halfnium
d) Thorium

View Answer

Answer: d [Reason:] Thorium is the main source of Monazite Sand.

7. Emission of β-particles during radioactive decay of a substance is from
a) nucleus
b) innermost shell
c) outermost shell
d) none of the mentioned

View Answer

Answer: a [Reason:] Emission of β-particles during radioactive decay of a substance is from the nucleus as all emissions are nuclear phenomenon.

8. A fertile material is the one, which can be
a) converted into fissile material on absorption of neutron
b) fissioned by either slow or fast neutrons
c) fissioned by slow (thermal) neutrons
d) fissioned by fast neutrons

View Answer

Answer: a [Reason:] A fertile material is the one, which can be converted into fissile material on absorption of neutron.

9. The half-life period of a radioactive element depends on its
a) temperature
b) pressure
c) amount
d) none of the mentioned

View Answer

Answer: d [Reason:] The half-life is independent of the mentioned factors.

10. Which is radioactive in nature?
a) Helium
b) Deuterium
c) Tritium
d) Heavy Hydrogen

View Answer

Answer: c [Reason:] Tritium is a radioactive element.

11. The most commonly used nuclear fuel in boiling water reactor is
a) enriched uranium
b) plutonium
c) natural uranium
d) monazite sand

View Answer

Answer: a [Reason:] Enriched uranium is the most commonly used nuclear fuel in boiling water reactor.

12. Enrichment of uranium is done to increase the concentration of __________ in the natural uranium
a) U-235
b) U-233
c) U-238
d) PU-239

View Answer

Answer: a [Reason:] Enrichment of uranium is done to increase the concentration of U-235 in the natural uranium.

13. Fuel for a nuclear reactor (thermal) is
a) Uranium
b) Plutonium
c) Radium
d) None of the mentioned

View Answer

Answer: a [Reason:] Uranium is the fuel for a thermal reactor.

14. The first underground nuclear test was conducted by India at
a) Pokhran
b) Kalpakkam
c) Jaisalmer
d) Narora

View Answer

Answer: a [Reason:] Pokhran had the very first underground nuclear test.

Set 4

1. Heat is generated in a nuclear reactor (thermal) by
a) fusion of atoms of uranium
b) absorption of neutrons in uranium atoms
c) combustion of nuclear fuel
d) fission of U-235 by neutrons

View Answer

Answer: d [Reason:] In a nuclear reactor, heat is generated by the fission of U-235 by neutrons.

2. Thorium-232 is converted into uranium-233 in a/an __________ nuclear reactor
a) heavy water moderated
b) fast breeder
c) thermal
d) enriched uranium

View Answer

Answer: b [Reason:] The conversion of Thorium-232 into Uranium-233 is done in a fast breeder.

3. An electron has a mass that is approximately __________ that of the proton.
a) 1/1836
b) 1
c) 1836
d) none of the mentioned

View Answer

Answer: a [Reason:] The mass of an electron is approx. 1/1836 times that of the mass of proton.

4. Which of the following may not need a control rod?
a) Candu Reactor
b) Liquid metal cooled reactor
c) Fast breeder reactor
d) None of the mentioned

View Answer

Answer: d [Reason:] None of the reactors mentioned above require a control rod.

5. The amount of a radioactive material (having a half-life of 100 years) remaining after 400 years will be __________ of its original weight.
a) 0.5
b) 0.25
c) 1/8
d) 1/16

View Answer

Answer: d [Reason:] The amount of a radioactive material (having a half-life of 100 years) remaining after 400 years will be 1/16 of its original weight [by using radioactive decay formula].

6. The amount of a radioisotope remaining un-decayed after a time equal to four times its half-life will be __________ percent.
a) 3.125
b) 6.25
c) 12.50
d) 25

View Answer

Answer: b [Reason:] The amount of a radioisotope remaining un-decayed after a time equal to four times its half-life will be 6.25 percent.

7. The time taken for a radioactive element to reduce to 50% of its original weight is __________ years, if its half-life period is 12 years
a) 24
b) 6
c) 18
d) 48

View Answer

Answer: c [Reason:] As per the radioactive decay rule, the required time will be 18 years.

8. Gas cooling as compared to water cooling of nuclear reactors
a) cannot attain a high temperature
b) is more efficient as gas has a higher specific heat.
c) can produce only saturated steam for feeding to power turbine
d) none of the mentioned

View Answer

Answer: d [Reason:] None of the mentioned effects are produced by Gas cooling in comparison to water cooling.

9. The decay product of tritium is?
a) Hydrogen
b) Deuterium
c) Lithium
d) Helium

View Answer

Answer: b [Reason:] Tritium decays into a Deuterium & a hydrogen atom.

Set 5

1. __________ of the coal is the basis for Seylor’s coal classification.
a) Proximate analysis
b) Calorific value
c) Ultimate analysis
d) Caking index

View Answer

Answer: c [Reason:] Ultimate Analysis of the coal is the basis for Seylor’s coal classification.

2. Yield of pitch from distillation of high temperature tar is around __________ percent.
a) 10
b) 25
c) 65
d) 100

View Answer

Answer: c [Reason:] Yield of pitch from distillation of high temperature tar is around 65 percent.

3. Caking index of the coal blend used for the manufacture of metallurgical coke should be around
a) 5
b) 40
c) 21
d) 48

View Answer

Answer: c [Reason:] Caking index is the ability of coal to be formed into cakes. Caking index of the coal blend used for the manufacture of metallurgical coke should be around 21.

4. High excess air in combustion of fuels results in
a) smoky flame
b) increased fuel consumption
c) incomplete combustion
d) none of the mentioned

View Answer

Answer: b [Reason:] High excess air in combustion of fuels results in increased fuel consumption. More the quantity of air in the fuel, more lean a mixture becomes.

5. The heat of combustion of a fuel
a) is equal to the heat of formation
b) is always negative
c) can’t be known without calculating it
d) is always positive

View Answer

Answer: b [Reason:] The heat of combustion of a fuel is always negative as always some heat has to be given (supplied) to the fuel for burning it.

6. _________ has the widest inflammability limit (explosion limit) of all the gases.
a) Carbon monoxide
b) Methane
c) Hydrogen
d) Acetylene

View Answer

Answer: d [Reason:] Acetylene has the widest inflammability limit (explosion limit) of all the gases. That is another factor due to which the gas is used in Gas welding.

7. Main constituents of benzol are
a) benzene, toluene & xylene
b) tar & creosote
c) ammonia & phenol
d) anthracene & phenol

View Answer

Answer: a [Reason:] Benzol comprises of benzene, toluene and xylene.

8. With increase in moisture content of coal, its
a) calorific value increases sometimes
b) bulk density always decreases
c) clinkering tendency during combustion increases
d) none of the mentioned

View Answer

Answer: d [Reason:] None of the mentioned factors behave in the manner when the moisture content increases.

9. Oxygen percentage (by weight) in atmospheric air is
a) 22
b) 20
c) 19
d) 21

View Answer

Answer: d [Reason:] 21 % of the atmospheric air is Oxygen.

10. In flue gas analysis by Orsat’s apparatus, carbon dioxide is absorbed by
a) cuporus chloride
b) dilute potassium carbonate
c) potassium hydroxide
d) alkaline pyragllol solution

View Answer

Answer: c [Reason:] In flue gas analysis by Orsat’s apparatus, carbon dioxide is absorbed by potassium hydroxide.