Ans: (a)
208. Atomic pile is used in: [SSC Graduate 2000]
   (a) the production of nuclear fission
   (b) the regulation of nuclear fission
   (c) the regulation of thermonuclear fusion
   (d) the atomic acceleration
Ans: (b)
209. Curie is the unit of:
   (a) radio activity
   (b) temperature
   (c) heat
   (d) energy
Ans: (a)
210. In the nuclear reactor, heavy water (D2O) is used in the form of : [RRB
   TC 2003]
   (a) moderator
   (b) coolant
   (c) castodian
   (d) controller
Ans: (a)
211. The mass-energy relation is the conclusion of : [SSC Graduate 2005]
   (a) quantum theory
   (b) general theory of relativity
   (c) arial theory of energy
   (d) special theory of relativity
Ans: (d)
212. The diode is a device which forces the current: [RRB Assist. Driver
   (a) to flow in one direction
   (b) to flow in both directions
   (c) not to flow in any direction
   (d) None of these