205) The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called

206) Plutonium (Pu₂₃₉) is produced

207) A petrol engine has compression ratio from

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.