Question

Figure shows the reading obtained while measuring the diameter of a wire with a screw gauge. The screw advances by 1 division on main scale when circular head is rotated once. Find least count of the screw gauge ?

Answer 1

Pitch is the linear distance traveled by one complete rotation of circular scale.

Since, 1 division travel in main scale so the pitch will be 1 mm.

Least count: $LC=p/n$

Here pitch $p=1mm$ and total number of circular divisions, $n=50$

So, $LC=1/50=0.02$ $mm$