An accuracy specification stated as "5 ppm of reading + 2 micro Volts" indicates what aspect of the measurement?

The accuracy specification "5 ppm of reading + 2 micro Volts" provides information about the precision and ranges of correct measurements for a certain instrument. This format indicates both a relative and an absolute accuracy.

The "5 ppm of reading" part highlights that the accuracy is dependent on the size of the measurement itself, meaning that for larger readings, the allowable error will increase in direct proportion. In contrast, the "2 micro Volts" portion establishes a fixed threshold for accuracy that is independent of the measurement size. This fixed threshold can be seen as a baseline or "floor" for the accuracy specification.

Understanding this helps to clarify that the specification conveys limits to how much the measurement can deviate from the true value, allowing operators to ascertain times when a measurement might be considered acceptable versus when it falls below necessary standards.

The other options don't accurately represent what this specific specification is addressing. For example, while measurement uncertainty is related to the overall accuracy, this specification specifically combines fixed and relative elements to create a "floor" specification. Therefore, the statement effectively characterizes a combination of accuracy limits rather than aspects like repeatability or drift alone.