A survey instrument must have an accuracy of what percentage?

For survey instruments used in radiation safety, accuracy is a critical factor to ensure that measurements of radiation exposure levels are reliable and within acceptable limits. The correct choice indicates that a survey instrument must have an accuracy of ±20%. This level of accuracy is generally seen as a standard for many applications related to radiation detection and measurement.

An accuracy of ±20% means that the measurements taken by the instrument can vary by 20% from the true value. This allowance is considered adequate for most radiation safety applications, balancing the need for precision with the practicalities of instrument performance and operational conditions often encountered in the field.

In contrast, tighter accuracy requirements, such as ±10% or ±15%, may be necessary in specific high-precision applications but are not the general standard for all survey instruments. More relaxed accuracy levels like ±25% could compromise the safety measures that rely on reliable radiation assessments. Thus, the choice of ±20% represents a reasonable compromise between the demands of accuracy and operational practicality in radiation safety measurements.