Explain the terms —

(i) pitch, and

(ii) least count of a screw gauge.

How are they determined?

1. Pitch of a screw gauge — The pitch of a screw gauge is the linear distance moved by its screw on the main scale when the circular scale is given one complete rotation.

2. Least count of a screw gauge — Least count of a screw gauge is the linear distance moved by its screw along the main scale when the circular scale is rotated by one division on it.

The pitch and least count of the screw gauge are determined by using the formula —

$\text{Least Count} = \dfrac{\text{Pitch of screw gauge}}{\text{Total no. of div on circular scale}}$