Which instrument provides higher precision for small-length measurements?

Which instrument provides higher precision for small-length measurements?

• A. Micrometer
• B. Vernier caliper
• C. Steel rule
• D. Centre punch

Answer: (A)

Measuring precision for small lengths depends on the instrument's least count—the smallest change it can reliably indicate. A micrometer uses a finely threaded screw to move the spindle toward the anvil, so each turn advances by a tiny, known amount. That lets you read measurements to around 0.01 millimetre on standard metric versions (and even to 0.001 mm with specialized types). That level of detail makes it the best choice when you need to quantify very small dimensions accurately. In contrast, a vernier caliper has a broader smallest increment, typically about 0.02 mm on metric versions, which is less precise for tiny measurements. A steel rule is simply a ruler with marked divisions; its smallest readable increment is usually 1 mm (or 0.5 mm on finer scales), which is far coarser. A centre punch isn’t used for measuring at all—it’s a marking tool for locating centers before drilling. So for small-length measurements requiring high precision, the micrometer provides the best precision among these options.

Measuring precision for small lengths depends on the instrument's least count—the smallest change it can reliably indicate. A micrometer uses a finely threaded screw to move the spindle toward the anvil, so each turn advances by a tiny, known amount. That lets you read measurements to around 0.01 millimetre on standard metric versions (and even to 0.001 mm with specialized types). That level of detail makes it the best choice when you need to quantify very small dimensions accurately.

In contrast, a vernier caliper has a broader smallest increment, typically about 0.02 mm on metric versions, which is less precise for tiny measurements. A steel rule is simply a ruler with marked divisions; its smallest readable increment is usually 1 mm (or 0.5 mm on finer scales), which is far coarser. A centre punch isn’t used for measuring at all—it’s a marking tool for locating centers before drilling.

So for small-length measurements requiring high precision, the micrometer provides the best precision among these options.