Question

Which of the following is true for measurement of surface roughness?

(a) 3 dimensional geometry can be easily measured

(b) Direction of measurement is perpendicular to the lay

(c) Direction of measurement is parallel to the lay

(d) Direction of measurement is parallel to the direction of the predominant surface marking

The question was posed to me in homework.

I would like to ask this question from Surface Roughness in portion Measurement of Surface Finish of Engineering Metrology

Answer 1

Right answer is (b) Direction of measurement is perpendicular to the lay

Easy explanation: There are difficulties in the measurement of surface roughness in three dimensional geometry, but for simplification purposes, it is reduced into two dimensional geometry. To measure, the direction is generally perpendicular to the direction of the predominant surface markings or “lay”.