Question

In a vernier caliper, 1 main scale division equals \(1\,\text{mm}\) and \(9\) MSD are divided into \(10\) equal parts by the vernier scale. When nothing was present in the jaws, zero of the vernier scale lies to the right of zero of the main scale and the \(7^{th}\) division of vernier scale coincides with one of the main scale divisions. Find zero error in the vernier caliper.

• A. \(0.3\ \text{mm}\)
• B. \(0.7\ \text{mm}\)
• C. \(-0.3\ \text{mm}\)
• D. \(-0.07\ \text{mm}\)

Answer 1

The Correct Option is B

Concept: Least count of vernier caliper: \[ \text{L.C.} = 1\text{ MSD} - 1\text{ VSD} \] Given: \[ 9\text{ MSD} = 10\text{ VSD} \] Step 1: Find least count \[ 1\text{ VSD} = \frac{9}{10}\text{ MSD} \] \[ \text{L.C.} = 1 - \frac{9}{10} \] \[ \text{L.C.} = 0.1\ \text{mm} \] Step 2: Find zero error 7th vernier division coincides with main scale division. \[ \text{Zero error} = 7 \times 0.1 \] \[ = 0.7\ \text{mm} \] Since vernier zero lies to the right of main scale zero, error is positive. \[ \boxed{+0.7\ \text{mm}} \]