How do micrometers and vernier calipers differ in measurement?

• A. A micrometer measures external dimensions; a caliper measures internal dimensions.
• B. A micrometer measures temperature; a caliper measures weight.
• C. A micrometer measures small thickness with high precision; a caliper measures external/internal dimensions and depth, often with a vernier scale.
• D. A micrometer measures voltage; a caliper measures current.

Answer: (C)

The main idea is how the tools differ in what they measure and how precisely they can do it. A micrometer is built for very small, precise thickness or outside dimensions. It uses a screw mechanism so a tiny turn moves the spindle just a small amount, giving readings that are extremely fine (often to 0.01 mm or 0.001 inch). Because of this, micrometers are ideal when you need a single dimension measured with high accuracy.

A vernier caliper (often just called a caliper) is a more versatile measuring instrument. It can measure external dimensions with its outside jaws, internal dimensions with its inside jaws, and depth with a depth rod. The vernier scale lets you read smaller increments than the main scale, but the overall precision is typically not as high as a micrometer for a single dimension. Digital versions exist too, but the core idea remains: calipers cover multiple types of measurements in one tool, while micrometers specialize in very precise, small-distance measurements.