Question

What is the range of readings up to distance of 9 metres in microptic autocollimator?

(a) 15 minutes of arc

(b) 20 minutes of arc

(c) 5 minutes of arc

(d) 10 minutes of arc

I got this question by my college professor while I was bunking the class.

My enquiry is from Optical Instruments for Angular Measurement topic in division Angular Measurement and Circular Division of Engineering Metrology

Answer 1

The correct option is (d) 10 minutes of arc

The best I can explain: A pair of target wires is used in this instrument. These wires are placed in the focal plane of a collimating lens. It is possible to read the tilt of reflector to normal upto 1/2 sec. of arc with the help of micrometer. The instrument has a range of readings of 10 minutes of arc up to 9 meter distance.