How should an analog survey meter be calibrated?

Calibrating an analog survey meter at two points approximately 33% and 66% of the scale's potential ensures that the meter provides accurate readings across a broad range of the measurement scale. This method allows for the correction of any non-linearity that may occur in the device, ensuring that both low and moderate radiation levels are accurately measured.

By selecting calibration points that are spread across the middle of the scale, you create a more effective representation of the overall performance of the meter. This is particularly important because analog meters may not respond uniformly across their entire range. Calibration at these specific intervals provides a more reliable indication of how the meter will perform in practice, especially when it's being utilized for radiation safety and monitoring tasks.

Other suggested calibration methods might not provide as effective a representation of the meter's performance or might overlook critical areas of the scale, making option B the optimal choice for accurate calibration.