The number of circular divisions of shown screw gauge are 50. It moves 0.5 mm on main scale in one rotation. The diameter of the ball is:

Options

A. 2.25mm
B. 2.20mm
C. 1.20mm
D. 1.25mm

Answer

C

Explanation

Zero error `=(5xx0.5)/50=0.05mm`
Actual measurement `=2xx0.5+(25xx0.5)/50-0.05=1+0.25-0.05=1.2` mm