Question

At what distance instrument is placed when straightness is determined with the help of autocollimator?

(a) 0.5 to 0.75 mm

(b) 0.5 to 0.75 cm

(c) 0.5 to 0.75 m

(d) 0.5 to 0.75 µm

I got this question in an internship interview.

My question is from Test for Straightness by using Spirit Level and Autocollimator topic in chapter Straightness, Flatness, Squareness, Parallelism, Circularity and Rotation of Engineering Metrology

Answer 1

Right option is (c) 0.5 to 0.75 m

Best explanation: In determining the straightness with the help of autocollimator instrument is placed at a distance of 0.5-0.75 m on any rigid support and it is completely independent of the surface to be tested.