Question

why do we use zero correction​

Answer 1

Explanation:

A vernier caliper is by definition a purely mechanical device. It cannot be “zeroed” before taking a reading, unlike, say, digital or dial calipers.

So, we need to take a zero measurement first, and compensate for the zero error.

Note, that for new, good quality vernier calipers, that that error will be less than readable. I