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

213) The octane number of petrol, generally available, is

214) The brake power is the power available

215) The slowing down of fast neutrons is desirable because slow moving neutrons are more effective than fast neutrons in triggering fission.

216) The normal heptane (C₇H₁₆) is given a rating of __________ octane number.