27) For welding plates of <5mm thickness, the edge require _____ beveling.

28) A 20 tooth pinion meshes with a 63 tooth gear. The gear ratio is

29) Thermal efficiency of a 2-stroke engine is _____ with respect to a 4-stroke engine.

30) In Electro-chemical Machining, material removal is due to

31) A rectangular bar with a circular hole is to be made of a material with actual maximum permissible stress of 150 Mpa. If stress concentration factor for the configuration is 3.0, what is the nominal average stress for sizing the section?