Quiz  /  Nuclear Engineering MCQ Intervieiw Questions and Answers

  • 1. 
    Neutrons have mass approximately equal to that of __________ atoms.

  • hydrogen
  • helium
  • deuterium
  • none of these

  • 2. 
    Pick out the wrong statement.

  • The ratio of the density of the ‘nucleus’ to that of the ‘atom’ is 1012 .
  • a-particle is identical with a doubly charged helium ion.
  • The mass of deuterium atom is half that of helium atom.
  • Gamma rays are high energy electrons.

  • 3. 
    The disintegration rate of a radioactive element

  • progressively increases.
  • progressively decreases.
  • remains constant throughout.
  • may increase or decrease depending on the material.

  • 4. 
    Heavy water used in the nuclear reactors to slow down the speed of neutrons is

  • highly purified water.
  • a compound of oxygen and deuterium.
  • water having dissolved salts of heavy metals.
  • none of these.

  • 5. 
    Pressure of CO2 gas (which is a coolant) in the Calder-Hall nuclear reactor is __________ kgf/cm2 .

  • 0.2
  • 7
  • 35
  • 50

  • 6. 
    The electric power generation cost in nuclear power plant is less than that in a coal based thermal power plant, mainly because the

  • fuel cost per unit power generated is less.
  • thermal efficiency of the former is higher.
  • maintenance cost of the former is less.
  • none of these.

  • 7. 
    Pick out the wrong statement.

  • Atoms with same number of nucleons but different number of protons are called isobars.
  • Atoms with same number of protons but different number of nucleons are called isoters.
  • Out of a, ß, and ?-rays, the one having maximum penetration power are ?-rays.
  • The product formed by emission of a-particle has mass number less by 4 units than the parent nuclide.

  • 8. 
    Molten sodium is used as a coolant in a fast breeder reactor, because of its

  • excellent moderating properties.
  • neutron breeding capability.
  • faster heat removal capability from the core.
  • capability to increase the reaction rate in the core.

  • 9. 
    Which of the following is the most harmful for the human being?

  • ß-rays
  • X-rays
  • ?-rays
  • ultra violet rays

  • 10. 
    Coolant used in a fast breeder reactor is

  • molten sodium
  • heavy water
  • ordinary water
  • helium

  • 11. 
    An element having large number of __________ is most easily subjected to nuclear fission.

  • protons
  • electrons
  • neutrons
  • nucleons

  • 12. 
    Heavy water is preferred over ordinary water as a coolant, because it

  • acts both as an efficient coolant as well as a moderator.
  • can be heated to a higher temperature without pressurizing.
  • is less prone to radiation damage.
  • all (a), (b) and (c).

  • 13. 
    The ratio of mass of a neutron to that of an electron is about 1839. What is the ratio of the mass of a proton to that of an electron?

  • 159
  • 1837
  • 2537
  • 10000

  • 14. 
    The number of neutrons in the nucleus of Uranium-233 (92U233) is

  • 141
  • 92
  • 233
  • 325

  • 15. 
    Which of the following gases has very high neutron capture cross-section, making it unsuitable as a coolant in nuclear reactor?

  • N2
  • He
  • CO2
  • H2

  • 16. 
    Nuclear power reactor located at Tarapur is of __________ type.

  • fast breeder
  • pressurised water
  • boiling water
  • gas cooled

  • 17. 
    Which of the following is not an ore of uranium?

  • Pitchblende
  • Kyanite
  • Carnotite
  • Rescolite

  • 18. 
    The main purpose of control rod in a nuclear reactor is to control the

  • chain reaction and hence the power output by regulating the number of secondary neutrons causing fission.
  • emission of hazardous radiation.
  • conversion of fissile material into fertile material.
  • velocity of the secondary neutrons.

  • 19. 
    Secondary cooling circuit is a must in molten sodium cooled fast breeder reactor for

  • achieving high degree of superheat in the steam.
  • faster heat removal rate from the core.
  • lowering the coolant circulation pressure.
  • avoiding the mixing of water with radioactive sodium, as it may cause explosion.

  • 20. 
    What is the average life of a radioactive atom having a ‘half life period’ of T?

  • 1.44 T
  • 0.144 T
  • 14.4 T
  • 2T

  • 21. 
    Use of molten metal as a coolant in fast breeder reactor helps in

  • rapid heat transfer from the core.
  • accelerating the reaction rate in the core.
  • breeding neutrons.
  • accelerating the neutrons.

  • 22. 
    Which of the following is a non-fissile material?

  • Plutonium-239
  • Uranium-235
  • Uranium-233
  • Thorium-232

  • 23. 
    Candu reactor is a __________ nuclcear reactor.

  • natural uranium fuelled heavy water cooled & moderated
  • highly enriched uranium (85% U-235) fuelled
  • homogeneous
  • fast breeder

  • 24. 
    Percentage of natural uranium present in uranium ore found in Jadugoda (Jharkhand) is

  • 0.1
  • 1
  • 3
  • 12

  • 25. 
    Nucleus of tritium has __________ neutrons.

  • 1
  • 2
  • 3
  • 5

  • 26. 
    Bhabha Atomic Research Centre (BARC) located at Trombay (near Bombay) has

  • five operating research reactors (namely Apsara, Cirus Zerelina, Purnima and Dhurva).
  • a 420 MW nuclear power plant.
  • a very large capacity (100 tons/yr) heavy water plant.
  • all (a), (b) and (c).

  • 27. 
    U-235 content in enriched uranium, that is normally used in power reactors (e.g., at Tarapur atomic power plant), is about __________ percent.

  • 85
  • 50
  • 3
  • 97

  • 28. 
    A fast breeder reactor

  • utilises fast neutrons for causing fission.
  • converts fertile material (e.g., U-238) into fissile material (Pu-239).
  • normally employs molten sodium as coolant.
  • all (a), (b) and (c).

  • 29. 
    H2 is a better coolant than CO2, due to its relatively

  • lower density.
  • higher specific heat.
  • non-reactivity to uranium.
  • lower neutron capture cross-section.

  • 30. 
    The half life period of a radiactive element is 100 days. After 400 days, one gm of the element will be reduced to __________ gm.

  • 1/4
  • 1/8
  • 1/2
  • 1/16

  • 31. 
    First experimental observation of nuclear fission was done by

  • Plane
  • Rutherford
  • Fermi
  • Hahn and Strassman

  • 32. 
    Coolant present in the primary circuit of a pressurised water reactor is high pressure

  • sub cooled water
  • saturated water
  • superheated steam
  • saturated steam

  • 33. 
    Extraction of uranium from its ore is done using __________ methods.

  • electrometallurgical
  • pyrometallurgical
  • chemical
  • physical beneficiation

  • 34. 
    The emission of an a-particle causes the resultant nucleus to have

  • more atomic weight and less atomic number.
  • less atomic weight and less atomic number.
  • less atomic weight and more atomic number.
  • none of these.

  • 35. 
    ‘Light water’ used as a coolant in nuclear reactor is nothing but

  • ordinary water.
  • mildly acidic (pH = 6) water.
  • mildly alkaline (pH = 8) water.
  • none of these.

  • 36. 
    Fast breeder reactors are most usable in India, because of our largest __________ deposits.

  • thorium
  • plutonium
  • uranium
  • none of these

  • 37. 
    The main ore of thorium is

  • pitchblende
  • monazite sand
  • limonite
  • galena

  • 38. 
    Critical energy should be __________ the neutron binding energy of the atom in order to initiate a nuclear fission.

  • equal to
  • less than
  • more than
  • either more or less==

  • 39. 
    In nuclear reactions, __________ number is conserved.

  • mass
  • atomic
  • both (a) & (b)
  • neither (a) nor (b)

  • 40. 
    The ratio of neutrons to protons of an element having a mass number and atomic number of 80 and 40 respectively is

  • 1
  • 0.5
  • 2
  • 4

  • 41. 
    Function of control rod in a nuclear reactor is to control

  • temperature
  • pressure
  • fuel consumption
  • absorption of neutrons

  • 42. 
    The main ore of uranium is

  • pitchblende
  • monazite sand
  • cassiterite
  • chalcopyrite

  • 43. 
    Which of the following nuclear materials is fissile?

  • Uranium-238
  • Thorium-232
  • Plutonium-239
  • None of these

  • 44. 
    Solar energy results from __________ reaction.

  • fission
  • combustion
  • thermonuclear
  • none of these

  • 45. 
    Heavy water (D2O) in a nuclear reactor serves as a

  • coolant
  • moderator
  • both (a) & (b)
  • neutron absorber

  • 46. 
    Atoms of U-238 and U-235 differ in structure by three

  • electrons and three protons
  • protons
  • neutrons
  • electrons

  • 47. 
    A radioactive isotope undergoes decay with respect to time following __________ law.

  • logarithmic
  • exponential
  • linear
  • inverse square

  • 48. 
    Main source of __________ is monazite sand.

  • uranium
  • polonium
  • hafnium
  • thorium

  • 49. 
    The first underground nuclear test was conducted by India at

  • Jaisalmer
  • Pokharan
  • Kalpakkam
  • Narora

  • 50. 
    Which of the following is not a good moderating material?

  • Concrete
  • Boron
  • 18/8 stainless steel
  • All (a), (b) and (c)

  • 51. 
    The molecular weight of heavy water is

  • 10
  • 18
  • 20
  • 36

  • 52. 
    The size of an atom is of the order of one

  • Angstrom
  • fermi
  • micron
  • mm

  • 53. 
    An ideal coolant for a nuclear reactor should

  • be a good absorber of neutrons.
  • be capable of attaining high temperature, only when it is pressurised.
  • have high density, but low heat transfer co-efficient.
  • be free from radiation damage and non-corrosive.

  • 54. 
    The phenomenon of nuclear fission is opposite to that of

  • radioactive decay
  • thermionic emission
  • nuclear fusion
  • combustion

  • 55. 
    A thermal nuclear reactor compared to a fast breeder reactor

  • uses slower neutrons for fission.
  • uses faster neutrons for fission.
  • gives higher power density.
  • requires less fuel to run at the same power level.

  • 56. 
    Coolant used in a boiling water reactor is

  • hydrogen gas
  • water
  • steam
  • a mixture of water & steam

  • 57. 
    Liquid metal (e.g, . molten sodium) is preferred as a coolant in case of a/an __________ reactor.

  • homogeneous
  • graphite moderated
  • fast breeder
  • enriched uranium (3% U-235) fuelled

  • 58. 
    In a pressurised water reactor (PWR), the

  • fuel is natural uranium and heavy water acts both as moderator & coolant.
  • coolant water boils in the core of the reactor.
  • coolant water is pressurised to prevent bulk boiling of water in the core.
  • use of moderator is not required.

  • 59. 
    Which of the following accounts for the maximum energy release in the nuclear fission process?

  • Kinetic energy of fission products
  • Radioactive decay of fission products
  • Instantaneous release of ?-rays
  • Kinetic energy of neutrons

  • 60. 
    Which of the following nuclear reactors is the most efficient thermodynamically while operating between the same temperature and pressure limits of the reactor?

  • Molten sodium cooled
  • CO2 gas cooled
  • Pressurised water
  • Boiling water

  • 61. 
    75% of a radioactive element decays in 6 hours. Its half life period is __________ hours.

  • 3/4
  • 1/6
  • 3
  • 4

  • 62. 
    The phenomenon of radioactivity was discovered by

  • Madam Curie
  • Bacquerrel
  • Roentgen
  • J.J. Thomson

  • 63. 
    Out of the following places, heavy water plant is not located at

  • Baroda
  • Ramagundam
  • Talcher
  • Tuticorin

  • 64. 
    A pressurised water reactor (PWR) uses pressurised water as a

  • coolant.
  • working fluid in power turbine.
  • moderator.
  • none of these.

  • 65. 
    Pick out the correct statement.

  • Positron is the antiparticle of electron.
  • In a-decay, the ratio of neutron to proton decreases.
  • Ionising power of ß-rays is higher than that of a-rays.
  • Speed of a-rays is more than that of ?-rays.

  • 66. 
    Which of the following is the best nuclear fuel?

  • Np- 239
  • U-234
  • Pu-239
  • Th-236

  • 67. 
    Uranium is recovered from its ore (pitchblende) by

  • froth floatation technique.
  • leaching with sulphuric acid.
  • smelting in a furnace.
  • dissolving in water.

  • 68. 
    Positron is a/an

  • nucleus having two protons.
  • helium nucleus.
  • electron with positive charge.
  • nucleus with one proton and one neutron.

  • 69. 
    Which of the following is a fuel for a fusion reactor (thermonuclear reactor)?

  • Deuterium and tritium
  • U-233
  • Thorium
  • Heavy water

  • 70. 
    Heavy water is used as a moderator in a

  • pressurised water reactor (PWR).
  • boiling water reactor (BWR).
  • Candu reactor.
  • molten sodium cooled reactor.

  • 71. 
    Nuclear power plant is not located at

  • Talcher (Orissa)
  • Rawatbhata (Rajasthan)
  • Kalpakkam (Tamilnadu)
  • Kaiga (Karnataka)

  • 72. 
    Isotopes of an element have the same

  • number of neutrons
  • mass number
  • electronic configuration
  • atomic weight

  • 73. 
    Extraction of uranium from its ore is done by __________ method.

  • chemical
  • pyrometallurgical
  • physical beneficiation
  • electrometallurgical

  • 74. 
    Radioactivity of an isotope is expressed in

  • barn
  • MeV
  • Curie
  • Ergs=

  • 75. 
    A heterogeneous reactor is the one, in which the moderator and the

  • coolant are different materials.
  • coolant are present in different phases (e.g., heavy water and graphite).
  • fuel are present in different phases (e.g. uranium and heavy water).
  • none of these.

  • 76. 
    The atomic mass of an element is fractional, because

  • of uncertainty principle.
  • it may have isobars.
  • it contains neutrons.
  • it may have isotopes.

  • 77. 
    Net efficiency of ordinary light water cooled nuclear reactor is about __________ percent.

  • 32
  • 52
  • 72
  • 88

  • 78. 
    The sum of masses of two nuclei produced in nuclear fission compared to the mass of original nucleus is

  • less
  • more
  • same
  • much more

  • 79. 
    The new nucleus formed after ß-decay of a radioactive element has

  • less atomic number
  • less atomic weight
  • more atomic number
  • more atomic weight

  • 80. 
    When the difference between mass number and atomic number of atoms of two or more elements are same, the atoms are termed as

  • isomers
  • isotopes
  • isobars
  • isotones

  • 81. 
    ‘Heavy water’ is termed as ‘heavy’ because it is

  • denser than water.
  • an oxide of deuterium.
  • a heavy liquid.
  • an oxide of heavier isotope of oxygen.

  • 82. 
    Uranium Corporation of India Limited (UCIL) engaged in the mining & concentration of uranium ore is located at

  • Alwaye (in Kerala)
  • Jadugoda (in Jharkhand)
  • Kalpakkam (in Tamilnadu)
  • Gopalpur coast (in Orissa)

  • 83. 
    Pick out the correct statement.

  • Loss of electrons from neutral atoms produces negative ions.
  • The radius of nucleus & atomic size are of the order of 10-12 cm & 10-8 cm respectively.
  • Gain of electrons by neutral atoms form cations.
  • Proton to neutron ratio in a stable nucleus is 2 : 1.

  • 84. 
    Quantity of fissionable material (i.e. U-235) in natural uranium is __________ percent.

  • 0.71
  • 6.31
  • 99.29
  • 12.73

  • 85. 
    Which of the following is present in Bhabha Atomic Research Centre (BARC) complex, Trombay (Bombay)?

  • Power reactor
  • Research reactor
  • Fast breeder reactor
  • Heavy water plant

  • 86. 
    Which of the following isotopes is not present in natural uranium?

  • U-238
  • U-234
  • U-235
  • U-232

  • 87. 
    Which of the following is not used as a moderator in nuclear reactor?

  • Molten sodium
  • Light water
  • Beryllium
  • Boron hydride

  • 88. 
    Percentage of the heavy water in ordi water is around

  • 0.015
  • 7.54
  • 0.71
  • 32.97

  • 89. 
    Water is a better coolant than a gas (like CO2, He, N2 etc.), because it

  • is a better neutron moderator as well.
  • requires comparatively smaller pumps and heat exchanger for a given heat transfer rate.
  • has a better heat transfer characteristics, and it can be pressurised to attain a high temperature.
  • all (a), (b) and (c).

  • 90. 
    Pick out the wrong statement.

  • The disintegration rate of a radioactive substance can not be increased by heating it.
  • Electrons have negligible mass and unit negative change.
  • Deuterium atom has one proton and two neutrons in its nucleus.
  • Cadmium is capable of absorbing neutrons.

  • 91. 
    Pressure in a Pressurised Water Reactor (PWR) is used for

  • maintaining constant pressure in the primary cooling circuit under varying loads.
  • superheating the steam.
  • pressurising the water in the primary coolant circuit.
  • none of these.

  • 92. 
    Energy produced in the nuclear fission is of the order of __________ MeV.

  • 20
  • 200
  • 1000
  • 2000

  • 93. 
    In ß-decay of radioactive material, the ratio of neutron to proton

  • increases.
  • remains same.
  • decreases.
  • is unpredictable; may increase or decrease.

  • 94. 
    Nuclear fuel usually used in a Boiling Water Reactor (BWR) is

  • plutonium
  • enriched uranium
  • natural uranium
  • thorium

  • 95. 
    Which is not a fissile nuclear material?

  • U-233
  • U-235
  • U-238
  • Pu-239

  • 96. 
    Heavy water plant is not located at

  • Talcher
  • Tuticorin
  • Ramagundam
  • Kota

  • 97. 
    Primary purpose of a __________ nuclear reactor is to supply a high neutron flux of the order of 1013 to 1014 neutrons/cm2 second.

  • research
  • power
  • breeder
  • homogeneous

  • 98. 
    The critical mass of a fissionable material can be reduced by

  • heating it.
  • cooling it.
  • surrounding it by neutron reflecting material.
  • surrounding it by neutron absorbing material.

  • 99. 
    Thorium-232 (a fertile material) on absorption of a neutron gets converted into __________ , which is a fissile material.

  • thorium-233
  • uranium-235
  • uranium-233
  • plutonium-239

  • 100. 
    Pick out the wrong statement.

  • Isotopes have the same number of protons & electrons, but different number of neutrons.
  • Hydrogen has two isotopes.
  • In ordinary hydrogen, 1H1 and 1H2 are present in the ratio 6400:1.
  • none of these.

  • 101. 
    Safety rods provided in nuclear reactors to guard against accidents, in case of earthquake are made of

  • high carbon steel.
  • molybdenum.
  • zircalloy.
  • boron or cadmium.

  • 102. 
    Percentage of heavy water in ordinary water is around

  • 0.015
  • 7.54
  • 0.71
  • 32.97

  • 103. 
    Which of the following undergoes fission reaction easily?

  • U-235
  • U-238
  • Th-232
  • none of these

  • 104. 
    Pick out the wrong statement.

  • a-particle emission from a radioactive element makes it electrically negative.
  • ß-particle emission from a radioactive element makes it electrically positive.
  • A radioactive element having a half life period of 20 years will completely disintegrated in 40 years.
  • The disintegration constant of a radioactive isotope is independent of pressure, temperature or concentration.

  • 105. 
    One ‘amu’ is equivalent to

  • 9.31 Mev
  • 931 eV
  • 931 MeV
  • 931 J

  • 106. 
    Unit of radioactivity is

  • barn
  • Fermi
  • Angstrom
  • Curie

  • 107. 
    The half life period of a radioactive element depends upon the

  • temperature
  • pressure
  • amount of element present
  • none of these

  • 108. 
    Indian monazite sand contains __________ percent thorium.

  • 10
  • 25
  • 60
  • 90

  • 109. 
    A radioactive substance does not emit

  • a-ray
  • proton
  • position
  • ß-ray

  • 110. 
    Out of the following, nucleus of __________ atom contains the largest number of neutrons.

  • U-235
  • U-238
  • U-239
  • Pu-239

  • 111. 
    ß-rays emission in radioactive disintegration is always accompanied by the emission of

  • ?-rays
  • a-rays
  • neutrons
  • none of these

  • 112. 
    Nuclear power generation capacity in India is

  • 3000 MW.
  • 10000 MW.
  • more than hydroelectric power generation capacity.
  • more than thermal power generation capacity.

  • 113. 
    Both tritium and deuterium have the same number of

  • neutrons
  • electrons
  • protons
  • nucleons

  • 114. 
    Hydrogen differs from deuterium in __________ properties.

  • radioactive
  • physical
  • chemical
  • all (a), (b) and (c)

  • 115. 
    Which of the following radiations is the least penetrating?

  • a-rays
  • ß-rays
  • ?-rays
  • X-rays

  • 116. 
    The radioisotope used to study the thyroid gland is

  • iodine
  • cobalt
  • iron
  • carbon

  • 117. 
    Enriched uranium means that, it contains

  • more than 0.71% of U-235.
  • only fertile material.
  • only fissile material.
  • no impurities.

  • 118. 
    In a homogeneous nuclear reactor, the __________ are mixed together.

  • fuel & coolant
  • fuel & moderator
  • coolant & moderator
  • none of these

  • 119. 
    Artificially produced radioactive isotopes are used for

  • power generation.
  • treatment of certain diseases.
  • initiating nuclear fission and fusion.
  • all (a), (b) and (c).

  • 120. 
    Uranium percentage in monazite sand is about

  • 0.01
  • 0.25
  • 1.2
  • 7

  • 121. 
    Which of the following reactors is operated at high neutron flux and low power level?

  • Breeder reactor.
  • Research reactor.
  • Heterogeneous reactor.
  • Liquid metal (e.g., molten sodium) cooled reactor.

  • 122. 
    Uranium ore is mined & concentrated in India at

  • Jadugoda(Jharkhand)
  • Kota (Rajasthan)
  • Tuticorin (Tamilnadu)
  • Talchar (Orissa)

  • 123. 
    Ceramic nuclear metals compared to solid nuclear metals have

  • higher melting points.
  • low strength at high temperature.
  • more chances of radiation damage.
  • poorer corrosion resistance.

  • 124. 
    Heavy water has maximum density at __________ C.

  • 4
  • 11.6
  • 0
  • 18.6

  • 125. 
    A fast breeder reactor

  • uses natural uranium as fuel.
  • does not require a moderator.
  • both (a) and (b).
  • neither (a) nor (b).

  • 126. 
    Which of the following factors is the most important in the site selection for a nuclear power plant?

  • Absence of earthquake prone zone in nearby areas.
  • Abundant availability of water.
  • Remotely located from residential areas.
  • Proximity to fuel source.

  • 127. 
    Radioactive decay of a material involves a __________ order reaction.

  • third
  • second
  • first
  • zero

  • 128. 
    Nuclear reactors are provided with shield to guard against the emission of mainly __________ rays.

  • X
  • a and ß
  • neutrons & gamma
  • infrared

  • 129. 
    Isotopes of an element have different

  • mass number
  • electronic configuration
  • nuclear charge
  • chemical properties

  • 130. 
    Biological shield is provided in a nuclear power reactor to protect the __________ from radiation damage.

  • fuel elements
  • operating personnels
  • walls of the reactor
  • none of these

  • 131. 
    Mass of a positron is same as that of a/an

  • electron
  • a-particle
  • proton
  • neutron

  • 132. 
    The mass number of an element is equal to the number of __________ in the nucleus.

  • electrons
  • neutrons
  • protons
  • neutrons plus protons (i.e., nucleons)

  • 133. 
    In the gaseous diffusion process of uranium enrichment, the natural uranium is converted into gaseous

  • uranium oxide
  • uranium hexaflouride
  • uranium carbide
  • uranium sulphate

  • 134. 
    Fast breeder test reactor at Kalpakkam is designed for using

  • thorium as a fertile material.
  • U-238 as a fertile material.
  • helium as a coolant.
  • uranium ore directly as a fuel.

  • 135. 
    Fuel for a fast breeder reactor is

  • plutonium
  • uranium
  • radium
  • neptunium

  • 136. 
    Number of secondary neutron emitted on fission of an atom of U-235 by slow neutron bombardment is

  • 3
  • 235
  • 200
  • 92

  • 137. 
    A control rod

  • should have small absorption cross-section.
  • is generally made of boron, hafnium or cadmium.
  • should have large absorption cross-section.
  • both (b) and (c).

  • 138. 
    Plutonium

  • is recovered from spent fuel from thermal nuclear reactor.
  • has much lower melting point (640C ) compared to thorium (1690C).
  • both (a) and (b).
  • neither (a) nor (b).

  • 139. 
    Fuel for a nuclear reactor (thermal) is

  • uranium
  • plutonium
  • radium
  • none of these

  • 140. 
    Percentage of U-238 in natural uranium is around

  • 0.71
  • 99.29
  • 0.015
  • 29.71

  • 141. 
    Emission of ß-particles during radioactive decay of a substance is from

  • innermost shell
  • nucleus
  • outermost shell
  • none of these

  • 142. 
    How many atoms are present in one gm-atom of an element?

  • 2 x 10 23
  • 6 x 10 23
  • 6 x 10 32
  • 5 x 10 5

  • 143. 
    Uranium ore is currently mined & concentrated at

  • Jadugoda
  • Ghatsila
  • Khetri
  • Alwaye

  • 144. 
    Which of the following ores contains maximum percentage of uranium?

  • Carnotite
  • Thorium.
  • Rescolite
  • Pitchblende

  • 145. 
    Atoms with same number of neutrons, but different number of nucleons are called

  • isotones
  • isobars
  • isotopes
  • isoters

  • 146. 
    Enrichment of uranium is done to increase the concentration of __________ in the natural uranium.

  • U-238
  • U-233
  • U-235
  • Pu-239

  • 147. 
    Thorium metal

  • resembles steel in appearance.
  • is less hard (in the range of silver).
  • is highly ductile.
  • all (a), (b) and (c).

  • 148. 
    Fast breeder nuclear reactors using enriched uranium as fuel may contain upto a maximum of __________ percent of U-235 (i.e. fissile material).

  • 15
  • 45
  • 65
  • 85

  • 149. 
    A fertile material is the one, which can be

  • converted into fissile material on absorption of neutron.
  • fissioned by slow (thermal) neutrons.
  • fissioned by fast neutrons.
  • fissioned by either slow or fast neutrons.

  • 150. 
    Nuclides having the same atomic numbers are termed as

  • isotopes
  • isomers
  • isotones
  • isobars

  • 151. 
    The most commonly used nuclear fuel in boiling water reactor is

  • enriched uranium
  • natural uranium
  • plutonium
  • monazite sand

  • 152. 
    Which one is radioactive in nature?

  • Helium
  • Deuterium
  • Heavy hydrogen
  • Tritium

  • 153. 
    __________ have the same mass number, but different nuclear charge.

  • Isotopes
  • Isobars
  • Isotones
  • none of these

  • 154. 
    The half life period of a radioactive element depends on its

  • temperature
  • pressure
  • amount
  • none of these

  • 155. 
    The time required for half of the __________ of a radioactive isotope to decay is called its half life.

  • nuclei
  • electrons
  • protons
  • neutrons

  • 156. 
    Which is a fertile nuclear fuel?

  • U-233
  • U-235
  • Pu-239
  • Th-232

  • 157. 
    Nuclear fuel generally used in reactors is uranium oxide instead of uranium, because the former has higher

  • melting point, hence can be subjected to higher temperature.
  • density ; hence core volume for a given power output would be smaller.
  • resistance to effects of irradiation.
  • all (a), (b) and (c).

  • 158. 
    Thorium can be converted into U-233 in a __________ reactor.

  • liquid metal cooled
  • fast breeder
  • thermal
  • swimming pool

  • 159. 
    A moderator __________ the neutrons.

  • slows down
  • absorbs
  • accelerates
  • reflects

  • 160. 
    Nuclear fuel complex, Hyderabad is engaged in the job of

  • manufacture of nuclear fuel elements/assemblies .
  • processing of uranium ore.
  • treatment of spent fuel.
  • none of these.

  • 161. 
    Radioactive decay is a __________ change.

  • chemical
  • nuclear
  • physical
  • none of these

  • 162. 
    __________ nuclear reactor does not require a heat exchanger to supply steam to power turbine.

  • Molten sodium cooled
  • Helium cooled
  • Boiling water
  • Pressurised water

  • 163. 
    If 4 gm of a radioisotope has a half life period of 10 days, the half life of 2 gm of the same istotope will be __________ days.

  • 5
  • 10
  • 20
  • 30

  • 164. 
    Pick out the wrong statement.

  • The nucleus of a hydrogen atom is identical with a proton.
  • A, ß-ray particle is identical with an electron.
  • Mass of an electron is about 1/1800th of the lightest nucleus.
  • Positron is heavier than a proton.

  • 165. 
    Specific gravity of uranium and plutonium is about

  • 9
  • 13
  • 19
  • 27

  • 166. 
    The function of moderators in nuclear reactor is to

  • slow down the secondary neutrons.
  • absorb the secondary neutrons.
  • control the chain reaction.
  • none of these.

  • 167. 
    Which of the following is not used as a nuclear fuel cladding material?

  • Zircalloy
  • Cadmium
  • Ceramics
  • Stainless steel

  • 168. 
    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
  • A- Z
  • A
  • Z

  • 169. 
    Thermal nuclear reactors using enriched uranium as fuel contains a maximum of __________ percent fissile material i.e. U-235.

  • 1
  • 2
  • 3
  • 7

  • 170. 
    Which of the following types of nuclear reactors is most prone to radioactive hazards?

  • Pressurised water reactor
  • Gas cooled reactor
  • Molten sodium cooled reactor
  • Boiling water reactor

  • 171. 
    Out of the following places, a nuclear power plant is not located at

  • Talcher (Orissa)
  • Kaiga (Karnataka)
  • Rawatbhata (Rajsthan)
  • Kalpakkam (Tamilnadu)

  • 172. 
    Research reactors are normally meant for

  • producing high neutron flux 1012-1013 neutrons/cm2, sec and studying the effect of neutron bombardment on dif ferent materials.
  • accelerating the neutrons.
  • power generation.
  • none of these

  • 173. 
    The ratio of volume of an atom to that of its nucleus is

  • 1012
  • 10-12
  • 10-8
  • 108

  • 174. 
    Sodium melts (at atmospheric pressure) at a temperature of __________ C.

  • 58
  • 98
  • 348
  • 588

  • 175. 
    Hydrogen bomb employs the nuclear fusion of

  • hydrogen
  • deuterium
  • tritium
  • helium

  • 176. 
    The largest stable nucleus is

  • U-235
  • U-238
  • Pb-206
  • Bi-209

  • 177. 
    In a nuclear explosion, the energy is released primarily in the form of __________ energy-

  • potential
  • thermal
  • kinetic
  • electrical

  • 178. 
    Tarapur atomic power station

  • has two boiling water reactors of American design.
  • has an installed capacity of 400 MW.
  • is the first power reactor in India, which became critical in 1969.
  • all (a), (b) and (c).

  • 179. 
    Fast breeder Test Reactor (FBTR) is located at

  • Kalpakkam (near Madras).
  • Kota (in Rajasthan).
  • BARC (Trombay).
  • Tarapur (in Maharashtra).

  • 180. 
    The type of pump used for the recirculation of molten sodium coolant in liquid metal cooled reactor is a/an __________ pump.

  • electromagnetic
  • reciprocating
  • centrifugal
  • volute

  • 181. 
    “Critical mass” is the minimum mass of nuclear fissile material required for the

  • sustainment of chain reaction.
  • power generation on commercial scale.
  • economic power generation.
  • none of these.

  • 182. 
    Energy equivlant to one atomic mass unit (amu) is __________ MeV.

  • 9.31
  • 93.1
  • 931
  • 9310

  • 183. 
    Velocity of the thermal neutron (< 0.025 eV) used for fission of U-235 is around __________ m/sec.

  • 1
  • 2200
  • 3 x 1011
  • 9 x 1021

  • 184. 
    MeV is the unit of

  • radioactivity
  • energy
  • potential difference
  • none of these

  • 185. 
    Hydrogen has __________ isotopes.

  • no
  • one
  • two
  • three

  • 186. 
    A homogeneous reactor is the one, in which the

  • fissile atoms are evenly distributed throughout the mass of nuclear reactor.
  • same substance (e.g. heavy water) is used as moderator & coolant.
  • the fuel and the moderator is mixed to form a homogeneous material.
  • all (a), (b) and (c).

  • 187. 
    Which one is the radioactive isotope of hydrogen?

  • Deuterium
  • Ortho-hydrogen
  • Tritium
  • None of these

  • 188. 
    Final product of uranium extraction plant at Jadugoda (Bihar) is

  • uranium
  • uranium oxide
  • uranium carbide
  • magnesium diuranate

  • 189. 
    Molten sodium (as a coolant in fast breeder reactor)

  • can’t attain high temperature at normal pressure.
  • is not at all corrosive, even at a higher temperature.
  • is highly radioactive at elevated temperatures and can cause explosion, when it comes in contact with air or water.
  • none of these

  • 190. 
    Which of the following is not, a fertile material?

  • Th-232
  • U-238
  • U-233
  • none of these

  • 191. 
    The atomic number of an element is equal to the number of __________ present in its atom.

  • neutrons
  • electrons
  • protons
  • either (b) or (c)

  • 192. 
    Which of the following is a moderating material used in nuclear reactor ?

  • Graphite.
  • Cadmium.
  • Zircalloy (an alloy of zirconium and aluminium).
  • Stainless steel.

  • 193. 
    A nuclear reactor can’t be used for

  • the production of radioisotopes.
  • supplying intense fields or beams of neutron for scientific experiments.
  • marine ship propulsion.
  • none of these.

  • 194. 
    Fission of U-235 on slow neutron bombardment can be represented by

  • 92U235 + 3 ?1 56Ba143 + 36Kr90
  • 92U235 + 0n1 56Ba143 + 36Kr90 + 3 0n1
  • 92U235 + 0n1 56Ba143 + 36Kr90 + 3 0n1 + Q (energy)
  • 92U235 + 0n1 92U236 + 30n1+ Q (energy)

  • 195. 
    The atomic number of a radioactive element is not changed, when it emits __________ rays.

  • a
  • ß
  • ?
  • a & ß

  • 196. 
    Ordinary water is not used as a moderator because, it

  • has a low absorption cross-section.
  • has a low scattering cross-section.
  • absorbs neutrons.
  • does not absorb neutrons.

  • 197. 
    Moderating material used in a thermal-reactor should be a

  • good absorber of neutrons.
  • solid substance.
  • poor absorber of neutrons.
  • none of these.

  • 198. 
    Which is used as a coolant in nuclear reactor due to its high capture cross-section ?

  • H2
  • N2
  • He
  • CO2

  • 199. 
    A boiling water reactor is the one, in which the

  • coolant water is allowed to boil in the core of the reactor.
  • coolant water, after being heated in the reactor core, generates steam in a boiler.
  • pressurised water is pumped into the core.
  • fuel and the coolant are thoroughly mixed to form a homogeneous solution.

  • 200. 
    Spent fuel from the nuclear thermal reactor contains

  • fission products
  • plutonium
  • unused fuel
  • all (a), (b) & (c)

  • 201. 
    Which of the following may not need a control rod ?

  • Liquid metal cooled reactor.
  • Fast breeder reactor.
  • Candu reactor.
  • None of these.

  • 202. 
    Thorium-232 is converted into uranium-233 in a/an __________ nuclear reactor.

  • thermal
  • fast breeder
  • heavy water moderated
  • enriched uranium

  • 203. 
    Fast breeder reactors do not

  • use Th-232 as fissile fuel.
  • convert fertile material to fissile material.
  • use fast neutrons for fission.
  • use molten sodium as coolant.

  • 204. 
    One ‘amu’ is equivalent to

  • 9.31 MeV
  • 931 eV
  • 931 Mev
  • 931J

  • 205. 
    Commercial power generation from fusion reactor is not yet possible, because

  • it is difficult to control fusion reaction.
  • the fuel required (e.g. deuterium and tritium) is scarce.
  • it is difficult to initiate fusion reaction.
  • quantity of fuel required for initiating fusion reaction is prohibitively high.

  • 206. 
    The amount of a radioisotope remaining undecayed after a time equal to four times its half life, will be __________ percent.

  • 3.125
  • 6.25
  • 12.50
  • 25

  • 207. 
    Which of the following may not need a moderator?

  • Candu reactor
  • Fast breeder reactor
  • Homogeneous reactor
  • Pressurised water reactor

  • 208. 
    Gas cooling as compared to water cooling of nuclear reactors

  • can not attain a high temperature.
  • is more efficient as gas has a higher specific heat.
  • can produce only saturated steam for feeding to power turbine.
  • none of these.

  • 209. 
    Which of the following is artificially produced as it does not occur in nature ?

  • Uranium-235
  • Uranium-233
  • Plutonium-239
  • Both (b) and (c)

  • 210. 
    The second underground nuclear test was conducted by India at

  • Jaisalmer
  • Pokhran
  • Kalpakkan
  • Narora

  • 211. 
    The amount of a radioactive material (having a half life of 100 years) remaining after 400 years will be __________ of its original weight.

  • 1/2
  • 1/4
  • 1/8
  • 1/16

  • 212. 
    Which is the most commonly used molten metal for cooling of nuclear reactors ?

  • Calcium
  • Sodium
  • Mercury
  • Zinc

  • 213. 
    An electron has a mass that is approximately __________ that of the proton.

  • 1836 (approximately)
  • 1/1836 (approximately)
  • 1
  • 8?

  • 214. 
    Which of the following is not a naturally occurring nuclear fuel

  • Uranium-238
  • Thorium-233
  • Plutonium-239
  • None of these

  • 215. 
    The mass number of an element is not changed, when it emits __________ radiations.

  • a & ß
  • ß & ?
  • ? & a
  • a, ß, & ??

  • 216. 
    The decrease in the atomic number is not observed in case of

  • electron capture
  • ß-emission
  • a-emission
  • positron emission?

  • 217. 
    Which of the following may be used to measure the rate of nuclear disintegration?

  • Geiger-Muller Counter
  • Cyclotron
  • Cold chamber
  • Mass spectrograph?
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