Question

when a measuring scale is used properly to the limit of precision, the last significant digit recorded for the measurement is said to be uncertain. please explain.

Explanation:

When using a measuring scale to its precision limit, the last significant digit is an estimate. Measuring tools have a smallest division. Beyond this, the value must be approximated. For example, with a ruler marked in millimeters, measurements between markings are estimated, introducing uncertainty.

Answer:

The last significant digit is uncertain because it is an estimated value based on the precision limit of the measuring scale.