For which surfaces, spirit level is used for testing straightness?
(a) Both horizontal and vertical surfaces
(b) Vertical surfaces
(c) In any plane
(d) Horizontal surfaces
The question was posed to me during an interview.
Question is from Test for Straightness by using Spirit Level and Autocollimator in section Straightness, Flatness, Squareness, Parallelism, Circularity and Rotation of Engineering Metrology