250+ TOP MCQs on Radioactive Decay & Half Life – II and Answers

Power Plant Problems on “Radioactive Decay & Half Life – II”.

1. Commercial power generation from fusion reactor is not yet possible, because __________
a) it is hard to control fission
b) it is hard to initiate fission
c) it is a non-periodic process
d) none of the mentioned
Answer: a
Clarification: The inability of controlled fission makes it tough to enable commercial power generation.

2. First experimental observation of nuclear fission was done by __________
a) Rutherford
b) Hahn & Strassman
c) Plane
d) Fermi
Answer: d
Clarification: Fermi made the first experimental observation of nuclear fission.

3. Function of control rod in a nuclear reactor is to control __________
a) pressure
b) temperature
c) fuel consumption
d) absorption of neutrons
Answer: d
Clarification: Control rods control the absorption of neutrons.

4. “Critical mass” is the minimum mass of nuclear fissile material required for the __________
a) sustainment of chain reaction
b) economic power generation
c) power generation on commercial scale
d) none of the mentioned
Answer: a
Clarification: “Critical mass” is the minimum mass of nuclear fissile material required for the sustainment of chain reaction.

5. Which of the following nuclear materials is fissile?
a) U-239
b) U-235
c) U-232
d) Pu-239
Answer: d
Clarification: Pu-239 is a fissile nuclear material.

6. Unit of Radioactivity is?
a) Curie
b) Angstrom
c) Fermi
d) Barn
Answer: a
Clarification: Curie is the unit of Radioactivity.

7. The ratio of neutrons to protons of an element having a mass number and atomic number of 80 and 40 respectively is?
a) 4
b) 3
c) 2
d) 1
Answer: d
Clarification: Number of neutrons = Atomic weight – Atomic number.

8. Critical energy should be __________ the neutron binding energy of the atom in order to initiate a nuclear fission.
a) less than
b) equal to
c) either more or less
d) more than
Answer: d
Clarification: Critical energy should be more than the neutron binding energy of the atom in order to initiate a nuclear fission.

9. Which is the main ore of uranium?
a) cassiterite
b) chalcopyrite
c) pitchblende
d) monazite sand
Answer: c
Clarification: Uranium comes from its main ore Pitchblende.

10. Nucleus of tritium has how many neutrons?
a) 1
b) 2
c) 3
d) 4
Answer: b
Clarification: There are 2 neutrons in tritium.

11. Percentage of natural uranium present in uranium ore found in Jadugoda (Jharkhand) is?
a) 2
b) 1
c) 0.1
d) 12
Answer: c
Clarification: Percentage of Uranium present in Jadugoda is 0.01%.

12. Coolant present in the primary circuit of a pressurised water reactor is high pressure __________
a) saturated steam
b) superheated steam
c) saturated water
d) sub cooled water
Answer: c
Clarification: Coolant present in the primary circuit of a pressurised water reactor is high pressure saturated water.

13. Candu reactor is a __________ nuclear reactor.
a) natural uranium fuelled heavy water cooled & moderated
b) highly enriched uranium (85% U-235) fuelled
c) homogeneous
d) fast breeder
Answer: a
Clarification: Candu reactor is a natural uranium fuelled heavy water cooled & moderated nuclear reactor.

14. Extraction of uranium from its ore is done using __________ methods.
a) chemical
b) pyrometallurgical
c) electrometallurgical
d) physical benefaction
Answer: a
Clarification: Extraction of uranium from its ore is done using chemical methods.

15. Atoms of U-238 and U-235 differ in structure by three __________
a) electrons
b) protons
c) neutrons
d) electrons & three protons
Answer: c
Clarification: The two atoms differ in the structure only in the number of neutrons.

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