When the flatness is measured with the use of optical flats, at what distance bands should be viewed?

Distance 5 times the diameter of optical flats

Distance 10 times the diameter of optical flats

Distance 8 times the diameter of optical flats

Distance 2 times the diameter of optical flats

When the flatness is measured with the use of optical flats, at what d

1.	When the flatness is measured with the use of optical flats, at what distance bands should be viewed?
A.	Distance 10 times the diameter of optical flats
B.	Distance 5 times the diameter of optical flats
C.	Distance 8 times the diameter of optical flats
D.	Distance 2 times the diameter of optical flats
Answer» B. Distance 5 times the diameter of optical flats