Question

What is the main use of steel cube reflector in autocollimator?

(a) To provide a 90 degree standard in 3 planes

(b) For general bench use

(c) Calibrate surface plate

(d) For setting but not checking perpendiculars

This question was addressed to me during an online exam.

My question is based upon Optical Instruments for Angular Measurement in portion Angular Measurement and Circular Division of Engineering Metrology

Answer 1

Correct choice is (a) To provide a 90 degree standard in 3 planes

Easy explanation: Steel cube reflector can be used as a general purpose reflector. It can be used for providing a 90 degree angle standard in three planes. It can be used for setting or checking perpendiculars.