Question

Which of the following is true for quartz flats?

(a) Have 200 to 400 % more wearing quality than optical flats

(b) Have 10 % more wearing quality than optical flats

(c) Have 10 % less wearing quality than optical flats

(d) Have 200 to 400 % less wearing quality than optical flats

I have been asked this question in exam.

My doubt stems from Interferometry Applied to Flatness Testing topic in division Measurement by Light-Wave Interference of Engineering Metrology

Answer 1

The correct choice is (a) Have 200 to 400 % more wearing quality than optical flats

The explanation: Quartz flats have more wearing qualities than optical flats. It is 200 to 400 percent more than optical flats. Working surfaces are finished to a high optical degree of flatness.