(d) All of these
Ans: (d)
375. The leader of the team who succeeded in constructing the first nuclear
   reactor (an atomic pile) in the world was
   (a) Albert Einstein
   (b) Enrico Fermi
   (c) HJ Bhabha
   (d) Sir Isaac Newton
Ans: (b)
376. Which of the following is fissionable?
   (a) U-234
   (b) U-235
   (c) U-238
   (d) Both (b) and (c)
Ans: (b)
377. The function of a moderator in a nuclear reactor is
   (a) to absorb unwanted neutrons
   (b) to slow down the fast neutrons to secure more effective hits on other
       nuclei
   (c) to decrease the number of fissile nuclei
   (d) to increase the number of fissile nuclei
Ans: (b)
378. A nuclear reactor is said to have become "critical" when
   (a) it stops due to malfunctioning
   (b) it starts emitting dangerous radioactive radiations
   (c) it is shut down to avoid explosion
   (d) it is ready to produce controlled energy
Ans: (d)
379. Why is nuclear fusion also known as thermonuclear reaction?
   (a) Fusion converts nuclear energy into heat
   (b) Fusion demands conditions of extremely high temperature to produce it
   (c) Fusion produces large amount of heat
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