145) In order to prevent knocking in spark ignition engines, the charge away from the spark plug should have

146) The size of a reactor at which the chain reaction can be initiated (i.e. when system becomes critical) with just enough fissionable material (called critical mass of fuel) is known as critical size of reactor.

147) A gas engine has a swept volume of 300 cm³ and clearance volume of 25 cm³. Its volumetric efficiency is 0.88 and mechanical efficiency is 0.90. The volume of the mixture taken in per stroke is

148) A supercharger receives air from the atmosphere surrounding the engine, compresses it to a higher pressure and then feeds it into the inlet valve of the engine.

149) Iso-octane (C₈H₁₈) has octane number of