Question 740 Deck Safety

The correct answer is B) At least 10 seconds. When using an oxygen indicator, you need to allow the sample time to stabilize within the instrument before taking the reading. This is because the oxygen content in the sample may change over time due to factors like temperature and pressure. Waiting at least 10 seconds ensures the reading is accurate and representative of the actual oxygen level in the sample. The other options are incorrect because 5 seconds is not long enough for the sample to fully stabilize (A), and 20 seconds is unnecessarily long (D). Option C, which states no wait is necessary, is incorrect because some wait time is required for the instrument to process the sample and provide an accurate reading.