Question

1. What is a micrometre screw gauge? $\left[1.5\text{marks}\right]$
2. State any one way to avoid backlash error in a screw gauge. $\left[0.5\text{mark}\right]$

Answer 1

1. Micrometre screw gauge: $\left[1.5\text{marks}\right]$
A screw gauge that has least count as $0.001\text{mm}$ or ${10}^{-6}\text{m}$ is called a micrometre screw gauge.
Such screw gauges with high degree of accuracy are used in optical measurements.

2. Precautions to be taken to avoid backlash error: $\left[0.5\text{mark}\right]$
In order to avoid backlash error, the screw is to be rotated in one direction only.
If it is required to change the direction of rotation, do not change the direction of rotation at once. Stop for a while before rotating the screw in the reverse direction.