49) The operation of making cone shaped enlargement at the end of the hole to provide recess for a flat head screw fitted into the hole is known as

50) Which of the following fire extinguisher would you use in order to extinguish an electrical fire?

51) Rag bolt is a type of

52) The circular pitch of a gear is given by where d = pitch diameter and t = numbers of teeth.

53) The process of forming thin sheet metal by revolving the job at high speed and pressing it against a former attached to head stock spindle is known as