208) In petrol engines, using a fixed octane rating fuel, the increase in engine speed will decrease the knocking tendency.

209) Materials which make good moderators do not make good reflectors.

210) The ignition of the charge by some hot surface within the engine before the passage of spark is called

211) Special reactors, called breeder reactors, supply a net gain of fissionable material.

212) The ratio of the indicated thermal efficiency to the air standard efficiency is known as