484. The fuel needed, with reflector in nuclear power plant, in order to generate sufficient neutrons to sustain a chain reaction, would be
A.More
B.Less
C.Same
D.Zero

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485. The efficiency of a nuclear power plant in comparsion to a conventional thermal power plant is
A.Same
B.More
C.Less
D.May be less or more depending on size

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486. Isotopes of same elements have
A.Same atomic number and different masses
B.Same chemical properties but different atomic numbers
C.Different masses and different atomic numbers
D.Different chemical properties and same atomic numbers

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487. Atomic number of an element in the periodic table represents the numbers of
A.Protons in the nucleus
B.Electrons in the nucleus
C.Neutrons in the nucleus
D.Electrons in the atom

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488. The mass number of a substance represents the sum of total number of
A.Protons and neutrons in an atom
B.Protons and electrons in an atom
C.Neutrons and electrons in an atom
D.Protons and neutrons in a nucleus

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489. A nuclear unit becoming critical means
A.It is generating power to rated capacity
B.It is capable of generating much more than rated capacity
C.There is danger of nuclear spread
D.Chain reaction that causes automatic splitting of the fuel nuclei has been established

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490. 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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