498. Which of the following nuclear reactor does not need a heat exchanger for generation of steam
A.Gas cooled
B.Liquid metal cooled
C.Pressurised water
D.Boiling water

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499. The most usable isotope of uranium is
A.U233
B.U235
C.(co u240
D.(C) U238

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500. The number of isotopes of hydrogen are
A.1
B.2
C.3
D.4

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501. The commonly used material for shielding is
A.Lead or concrete
B.(h) lead and tin
C.Graphite or cadmium
D.Thick galvanised sheets

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502. The main interest of shielding in nuclear reactor is protection against
A.X-rays
B.Infra-red rays
C.Oc,j3, and y rays
D.Neutrons and gamma rays

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503. Reflector in nuclear plants is used to
A.Return the neutrons back into the core
B.ShIeld the radioactivity completely
C.Check polllution
D.Conserve energy

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504. The energy required to be applied to a radioactive nucleus for the emission of a neutron is
A.1 MeV
B.2.4 MeV
C.4.3 MeV
D.7.8 MeV

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