If the zero mark of circular scale above the base line of main scale, the screw gauge is said to be positive zero error.

If the zero mark of circular scale coincides with the base line of main scale, the screw gauge is said to be free from zero error.

In the figure, the pitch of the screw is 1 mm. Find the reading represented in the diagram.

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$

What is zero error of the screw gauge and how to identify the zero error?

The least count of the screw gauge shown in the diagram is $0.001 \text{cm}$. Determine its zero error in the units of $\text{mm}$.

When a reading is taken with the help of Vernier calipers, the positions of the main scale and Vernier are as shown in the figure, find the correct reading, if there is an error of $+0.02 \mathrm{cm}$

If the zero mark of circular scale below the base line of main scale, the screw gauge is said to be positive zero error.