Which measuring tool is capable of measuring depth as well as external and internal dimensions with moderate precision?

• A. A micrometer
• B. A caliper
• C. A ruler
• D. A stopwatch

Answer: (B)

Calipers are versatile measuring tools designed to handle three ways of measuring. They have large jaws for measuring external dimensions, smaller jaws inside openings for internal dimensions, and a depth-measuring rod that extends from the end to reach down into recesses. This combination lets you measure outside size, inside size, and depth with moderate precision—often around 0.01 mm (0.001 in) depending on the caliper. A micrometer provides higher precision for external measurements but isn’t suited for internal measurements or depth. A ruler is too coarse for precise internal or depth measurements, and a stopwatch isn’t a dimensional measuring tool. So the tool that covers depth along with external and internal measurements is the caliper.