Question

Which of the following option is true for optical flats used in flatness testing?

(a) Type A optical flats has only one surface flat

(b) Optical flats are better than quartz flats

(c) White light source is very important in measurement by light wave interference

(d) Working surfaces of optical flats are cylindrical

This question was posed to me in class test.

The doubt is from Interferometry Applied to Flatness Testing in section Measurement by Light-Wave Interference of Engineering Metrology

Answer 1

Right answer is (a) Type A optical flats has only one surface flat

Explanation: Type A optical flats have only one flat surface. Working surface in such type of optical flats is indicated by an arrow head on the cylindrical surface. This arrow head is pointing towards the working surface.