The discrimination, which is the smallest graduation or increment of a measuring instrument, is also called __________.

• A. Resolution
• B. Accuracy
• C. Precision
• D. Tolerance

Answer: (A)

The main idea is readout granularity. The smallest graduation or increment an instrument can distinguish is its resolution, which is essentially its discrimination—the finest change it can reveal on its scale or display. For example, a ruler marked in millimeters can resolve differences of 1 mm, while a vernier caliper that reads to 0.02 mm can distinguish 0.02 mm changes. This concept is about what the instrument can actually differentiate in a measurement, not about how close the reading is to the true value or how repeatable readings are.

Accuracy describes how close a measurement is to the true value, which is a different quality. Precision refers to the consistency or repeatability of measurements under the same conditions, not the smallest readable increment. Tolerance is the allowable range of variation for a dimension, again separate from the instrument’s ability to discriminate small changes.