In a vernier micrometer, what is the purpose of the Vernier scale?

In a vernier micrometer, what is the purpose of the Vernier scale?

• A. Provide finer resolution by aligning with the main scale
• B. Lock the spindle
• C. Measure depth
• D. Indicate zero

Answer: (A)

The Vernier scale is used to gain finer measurement precision by subdividing the main-scale division. As you close the spindle, you watch which line on the Vernier scale most closely aligns with a line on the main scale. That alignment provides a fractional part of the main-scale division, and when you add that to the main-scale reading, you obtain a more precise measurement than the main scale alone. This interpolation between scales is what gives the micrometer its higher resolution. The other features—locking the spindle, measuring depth with a depth rod, or indicating zero—are separate aspects of the instrument and not the purpose of the Vernier scale.

The Vernier scale is used to gain finer measurement precision by subdividing the main-scale division. As you close the spindle, you watch which line on the Vernier scale most closely aligns with a line on the main scale. That alignment provides a fractional part of the main-scale division, and when you add that to the main-scale reading, you obtain a more precise measurement than the main scale alone. This interpolation between scales is what gives the micrometer its higher resolution.

The other features—locking the spindle, measuring depth with a depth rod, or indicating zero—are separate aspects of the instrument and not the purpose of the Vernier scale.