250+ TOP MCQs on Chemical & Nuclear Reactions – I and Answers

Power Plant Engineering Multiple Choice Questions on “Chemical & Nuclear Reactions – I”.

1. Heat is generated in a nuclear reactor (thermal) by __________
a) fusion of atoms of uranium
b) absorption of neutrons in uranium atoms
c) combustion of nuclear fuel
d) fission of U-235 by neutrons
Answer: d
Clarification: In a nuclear reactor, heat is generated by the fission of U-235 by neutrons.

2. Thorium-232 is converted into uranium-233 in a/an __________ nuclear reactor.
a) heavy water moderated
b) fast breeder
c) thermal
d) enriched uranium
Answer: b
Clarification: The conversion of Thorium-232 into Uranium-233 is done in a fast breeder.

3. An electron has a mass that is approximately __________ that of the proton.
a) 1/1836
b) 1
c) 1836
d) none of the mentioned
Answer: a
Clarification: The mass of an electron is approx. 1/1836 times that of the mass of proton.

4. Which of the following may not need a control rod?
a) Candu Reactor
b) Liquid metal cooled reactor
c) Fast breeder reactor
d) None of the mentioned
Answer: d
Clarification: None of the reactors mentioned above require a control rod.

5. The amount of a radioactive material (having a half-life of 100 years) remaining after 400 years will be __________ of its original weight.
a) 0.5
b) 0.25
c) 1/8
d) 1/16
Answer: d
Clarification: The amount of a radioactive material (having a half-life of 100 years) remaining after 400 years will be 1/16 of its original weight [by using radioactive decay formula].

6. The amount of a radioisotope remaining un-decayed after a time equal to four times its half-life will be __________ percent.
a) 3.125
b) 6.25
c) 12.50
d) 25
Answer: b
Clarification: The amount of a radioisotope remaining un-decayed after a time equal to four times its half-life will be 6.25 percent.

7. The time taken for a radioactive element to reduce to 50% of its original weight is __________ years if its half-life period is 12 years.
a) 24
b) 6
c) 18
d) 48
Answer: c
Clarification: As per the radioactive decay rule, the required time will be 18 years.

8. Gas cooling as compared to water cooling of nuclear reactors __________
a) cannot attain a high temperature
b) is more efficient as gas has a higher specific heat
c) can produce only saturated steam for feeding to power turbine
d) none of the mentioned
Answer: d
Clarification: None of the mentioned effects are produced by Gas cooling in comparison to water cooling.

9. What is the decay product of tritium?
a) Hydrogen
b) Deuterium
c) Lithium
d) Helium
Answer: b
Clarification: Tritium decays into a Deuterium & a hydrogen atom.