- Which of the following is used as a moderator in nuclear reactors?
a) Uranium
b) Radium
c) Thorium
d) Graphite
Answer: d - The Sun’s energy is primarily due to:
a) Atomic bomb reactions
b) Hydrogen bomb detonation
c) Nuclear fusion
d) Combustion
Answer: c - What is “heavy water” used in nuclear reactors?
a) Water rich in minerals
b) Ozonized water
c) Water with heavy metal ions
d) Water containing heavy hydrogen isotopes
Answer: d - The radiant energy of the Sun is generated by:
a) Disintegration
b) Nuclear fission
c) Nuclear fusion
d) Combustion
Answer: c - In nuclear reactors, neutrons are slowed down by the:
a) Fissionable material
b) Moderator
c) Control rods
d) Coolant system
Answer: b - The massive energy of the Sun is generated by:
a) Fission of uranium
b) Fusion of hydrogen nuclei into helium
c) Fusion of deuterium and tritium
d) Fission of tritium into helium
Answer: b - Alpha particles are:
a) Twice as massive as beta particles
b) Negatively charged particles
c) Similar to helium nuclei
d) Weaker in ionizing power than gamma rays
Answer: c - The main reason for the Sun’s energy is:
a) Nuclear fission
b) Radioactivity
c) Heat
d) Nuclear fusion
Answer: d - The radiation that penetrates deepest into the human body is:
a) Ultraviolet radiation
b) Alpha particles
c) Beta particles
d) Gamma rays
Answer: d - What happens during nuclear fusion?
a) A heavy nucleus splits after neutron bombardment
b) A heavy nucleus spontaneously breaks apart
c) Two light nuclei combine to form a heavier nucleus
d) A light nucleus spontaneously breaks apart
Answer: c - Which isotope of uranium is used in atomic reactors?
a) U-235
b) U-236
c) U-237
d) U-232
Answer: a - In a nuclear reactor, heavy water is used to:
a) Transfer heat from the reactor
b) Provide high-speed neutrons
c) Slow down fast neutrons
d) Increase the speed of neutrons
Answer: c - Which of the following can absorb neutrons and control chain reactions in nuclear fission?
a) Boron
b) Heavy water
c) Uranium
d) Plutonium
Answer: a - Which of the following is a thermonuclear reaction?
a) 92U238 + 0n1 → 93N239 + -1e0
b) 1H1 + 1H1 → 2He4 + 2(+1e0)
c) 92U238 + 6C12 → 98Cf246 + 40n1
d) 13Al27 + 2He4 → 15P30 + 0n1
Answer: b - Another commonly used moderator in nuclear reactors is:
a) Thorium
b) Graphite
c) Cesium
d) Radium
Answer: b - Which element belongs to the 4n radioactive series?
a) Pb-206
b) Pb-207
c) Pb-208
d) Pb-209
Answer: c - Which radiation is not emitted during natural radioactivity?
a) Alpha rays
b) Beta rays
c) Gamma rays
d) Cathode rays
Answer: d - If an element X emits one alpha and two beta particles in three steps, the final product is:
a) An isobar of X
b) An isotope of X
c) X itself
d) An isotone of X
Answer: b - Which of the following has the lowest penetration power?
a) Alpha rays
b) Beta rays
c) Gamma rays
d) Delta rays
Answer: a - An isobar of a nuclide is formed by:
a) One alpha emission
b) One beta emission
c) One alpha + one beta emission
d) Two alphas + two betas emission
Answer: b - U-235 belongs to which radioactive decay series?
a) Thorium series
b) Actinium series
c) Uranium series
d) Neptunium series
Answer: b - The loss of a beta particle results in:
a) Increase of one proton
b) Decrease of one neutron
c) Both a and b
d) None of these
Answer: c