Power Plant Questions and Answers – Radioactive Decay & Half Life – I

This set of Power Plant Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Radioactive Decay & Half Life – I”.

1. Fast breeder nuclear reactors using enriched uranium as fuel may contain upto a maximum of __________ percent of U-235 (i.e. fissile material).
a) 15
b) 45
c) 65
d) 85
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2. __________ have the same mass number, but different nuclear charge.
a) Isotones
b) Isobars
c) Isotopes
d) Isoemtropic
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3. Atoms with same number of neutrons, but different number of nucleons are called __________
a) Isobars
b) Isotones
c) Isotopes
d) Isoters
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4. The half-life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a Geiger Muller counter from its known quantity. If the half-life period of a radioactive substance is one month, then?
a) it will completely disintegrate in two months
b) l/8th of it will remain intact at the end of four months
c) 3/4th of it will disintegrate in two months
d) it will completely disintegrate in four months
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5. Which of the following ores contains maximum percentage of uranium?
a) Rescolite
b) Thorium
c) Pitchblende
d) Carnotite
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6. Percentage of U-238 in natural uranium is around __________
a) 29.71
b) 99.29
c) 0.015
d) 0.71
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7. Uranium ore is currently mined & concentrated at __________
a) Khetri
b) Alwaye
c) Ghatsilla
d) Jadugoda
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8. Graphite is used in nuclear reactor as __________
a) lubricant
b) fuel
c) retarder of neutron velocity
d) insulation lining of the reactor
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9. A fast breeder reactor employs __________
a) U-235 as a fuel
b) water as a coolant
c) graphite as a moderator
d) none of the mentioned
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10. A radioactive isotope undergoes decay with respect to time following __________ law.
a) logarithmic
b) exponential
c) inverse square
d) linear
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11. U-235 content in enriched uranium, that is normally used in power reactors (e.g., at Tarapur atomic power plant), is about __________ percent.
a) 50
b) 3
c) 85
d) 97
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12. The half-life period of a radioactive element is 100 days. After 400 days, one gm of the element will be reduced to __________ gm.
a) 1/2
b) 1/4
c) 1/8
d) 1/16
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13. Which of the following is a non-fissile material?
a) Pu-239
b) U-235
c) U-232
d) Th-232
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14. Fast breeder reactors are most usable in India, because of our largest __________ deposits.
a) Uranium
b) Plutonium
c) Thorium
d) None of the mentioned
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15. Which is the main ore of thorium?
a) Magnetite
b) Monazite Sand
c) Pitchblende
d) None of the mentioned
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Sanfoundry Global Education & Learning Series – Power Plant Engineering.

To practice all areas of Power Plant Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.