Question

What is meant by roughness?

(a) Minute succession of hills of different height

(b) Minute succession of valleys and hills of different height and varied spacing

(c) Minute succession of valleys and hills of same height and same gap

(d) Minute succession of valleys of different depth

I had been asked this question in semester exam.

My question is taken from Surface Roughness topic in division Measurement of Surface Finish of Engineering Metrology

Answer 1

Right choice is (b) Minute succession of valleys and hills of different height and varied spacing

Explanation: Imperfections are bound to be on surface and they take the form of succession of hills and valleys which vary in height and spacing which result in irregularity of the surface. Roughness is the form of these minute imperfections.