Question

How many microscopes are required to marking a circular disc into 90^o divisions?

(a) 1

(b) 2

(c) 3

(d) 4

This question was posed to me during an online exam.

I'd like to ask this question from Caliper Principle in division Angular Measurement and Circular Division of Engineering Metrology

Answer 1

Correct choice is (b) 2

To explain I would say: If the caliper principle is applied for marking a circular disc into 90 degree divisions. Then, in this method, we require the use of two microscopes for taking readings at two different positions simultaneously.