15. A nuclear fission produces energy of following order in MeV
A.20
B.200
C.2000
D.20000

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16. Moderator in nuclear plants is used to
A.Reduce temperature
B.Extract heat from nuclear reaction
C.Control the reaction
D.Cause collision with the fast moving neutrons to reduce their speed

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17. The main interest of shielding in nuclear reactor is protection against
A.X-rays
B.Infra-red rays
C.α, β, and γ rays
D.Neutrons and gamma rays

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18. U235 will undergo fission by
A.High energy (fast) neutrons alone
B.Low energy (slow) neutrons alone
C.Either fast or slow neutrons
D.Medium energy neutrons

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19. Electron-volt is the unit of
A.Atomic power
B.Energy
C.Voltage
D.Radio activity

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20. Superheated steam is generated in following reactor
A.Boiling water
B.Gas cooled
C.Pressurised water
D.All of the above

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21. A nuclear fission is initiated when the critical energy as compared to neutron binding energy of the atoms is
A.Same
B.More
C.Less
D.There is no such criterion

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