Question

What is the dimension of polygon between top and supporting surfaces for a type 2 precision polygon as per IS: 6987-1973?

(a) 75 mm

(b) 150 mm

(c) 300 mm

(d) 600 mm

I got this question in homework.

Origin of the question is Precision Polygons in chapter Angular Measurement and Circular Division of Engineering Metrology

Answer 1

Correct choice is (b) 150 mm

For explanation I would say: As per IS : 6987-1973, there are three types of precision polygons that is ‘type-1’, ‘type-2’ and ‘type-3’. The dimension of polygon between the top surface and the supporting surface is 75 mm for type -1,150 mm for type-2 and 300 mm for type-3.