What is a primary function of a Vernier caliper?

A Vernier caliper is a precision instrument used primarily for measuring both internal and external dimensions of an object. It consists of a main scale and a sliding vernier scale, which allows for measurement with a high degree of accuracy. By using the caliper's jaws, users can measure the outside dimensions, such as the width or diameter of an object, and with the internal jaws, they can measure the internal dimensions, such as the diameter of a hole or the width of a groove. This dual capability makes the Vernier caliper a versatile tool for ensuring precise measurements in various applications, including engineering and manufacturing.

While some instruments specialize in measuring only external dimensions or other specific tasks, the versatility of the Vernier caliper in measuring both internal and external dimensions distinguishes it as a vital tool in various fields. Other choices outline functions that either pertain to entirely different tools or capabilities, such as cutting keyholes or measuring angles, which are not applicable to the Vernier caliper.