Question

A vernier callipers has its main scale graduated in mm and 10 divisions on its vernier scale are equal in length to 9 mm. When the two jaws are in contact. the zero of vernier scale is ahead of zero of main scale and 3rd division of vernier scale coincides with a main scale division. The zero error of the vernier callipers is $3\times {10}^{-x}cm$. Find the value of x.

Answer 1

The least count of given vernier scale is:

$L.C=\frac{1-9}{10}=0.1mm=0.01cm$

If third division of vernier scale coincides with main scale division then the zero error is:

vernier division ahead of zero of main scale $\times$ least count

$=3\times 0.01cm=0.03cm$

And it is ahead of main scale then error is positive

$=+3\times 0.01cm=+0.03cm$