Question

Calculate the least count of the screw gauge.
A.\[{{10}^{-2}}cm\]
B.\[{{10}^{-3}}mm\]
C.\[{{10}^{-3}}cm\]
D.\[{{10}^{-3}}m\]

Answer 1

Hint: A gauge measure is otherwise called a micrometer is an accuracy instrument. It is utilized for estimating distance across of round articles for the most part wires, with an exactness of 0.01mm.

Complete answer:
It comprises an empty chamber mounted on a U outline. The empty chamber prompts a fastener which is intended for fine change. The U outline comprises a level end known as stud and a screw on the opposite side. This screw can be shifted inside the nut by fitting in the U outline by pivoting the empty chamber called the thimble. This is known as the fundamental scale. The empty chamber or the thimble is graduated into 100 equivalent parts so the least count is \[{{10}^{-2}}cm\]. This is known as the round scale.

Screw-measure:
The screw has a referred pitch, for example, 0.5 mm. Pitch of the screw is the separation shifted by the axle per transformation. Henceforth for this situation, for one insurgency of the screw, the axle pushes ahead or in reverse 0.5 mm. This development of the axle has appeared on an engraved direct millimeter scale on the sleeve. On the thimble, there is a round scale which is separated into 50 equivalent parts.
Least count=pitch/number of divisions of thimble
\[0.5/50=0.01\text{ }mm.\]

The correct answer is A.

Note:
At the point when the iron block and shaft end are gotten contact, the edge of the round scale ought to be at the zero of the sleeves (straight scale) and the zero of the roundabout scale ought to be inverse to the datum line of the sleeve. One division of thimble =0.01 mm with reference to a straight line on the sleeve. This the least check of screw measure or micrometer.