Multiple Choice Question (MCQ)

Question: What is the relation between pitch and lead in multistart thread?
A. Lead = No. start x pitch
B. Lead = Pitch
C. Lead = 1/2 pitch
D. Lead = 1/3 x pitch
Correct Answer: Lead = No. start x pitch
Explanation

A welding helmet, commonly referred to as a “hood,” is one of the most important pieces of personal protective equipment that a welder must have. An adequate helmet protects the eyes and skin not only from severe sparks, but also from potentially vision-damaging ultraviolet and infrared rays emitted by the arc.

Helmet with filtered colour glass is used to protect face from UV and Infra-red radiation during welding.