Question

what is mean by zero error of Vernier Calliper how it is determined draw a neat diagram to explain it how it is taken in account to get a correct measurement

Answer 1

First of all try to understand what is a vernier caliper and its structure. A vernier caliper uses two scales, main scale and the vernier scale. They are attached together. Before using it, try to bring the ends of the two scales together, that is near the zero of the main scale.

You will understand this better by this diagram, wait.

well, my drawing is not so good, but see the zeroes of the two scales together.

Now, what if the zeroes don't lie together,

Check out my next diagram, wait

See here the zeroes are not corresponding together. This is called zero error.

It can now be of two types: positive zero error and negative zero error.

When the zero is to the right of the main scales zero it is called positive zero error and the amount of error will be subtracted from the total reading.
when the zero is to the left of the main scale zero it is called negative zero error, and the amount of error will be added to the total reading.

Hope the concept is clear now.

Answer 2

Answer:

If the zero of vernier scale doesn't coincide with the zero of the main scale, then the instrument i.e., vernier caliper has an error called zero error. Zero error is always algebraically subtracted from the measured length.