Which number represents the Vernier scale graduation of a micrometer?

Which number represents the Vernier scale graduation of a micrometer?

• A. .001
• B. .0001
• C. .0005
• D. .0002

Answer: (B)

The micrometer’s precision comes from two scales: the main scale and the Vernier scale. The main scale gives readings in 0.001 inch increments, while the Vernier scale subdivides each thousandth to provide finer resolution. Ten divisions on the Vernier line up with nine on the main scale, giving a least count of 0.0001 inch. That is why the Vernier graduation is 0.0001 inch. The other options are either the main-scale step (0.001) or larger increments that don’t represent the Vernier’s smallest readable increment.

The micrometer’s precision comes from two scales: the main scale and the Vernier scale. The main scale gives readings in 0.001 inch increments, while the Vernier scale subdivides each thousandth to provide finer resolution. Ten divisions on the Vernier line up with nine on the main scale, giving a least count of 0.0001 inch. That is why the Vernier graduation is 0.0001 inch. The other options are either the main-scale step (0.001) or larger increments that don’t represent the Vernier’s smallest readable increment.