For H2S detection, sensitized tapes indicate H2S presence by means of discoloration of an exposed spot on the tape. The shade of the color on the spot depends upon the concentration of H2S and which of the following factors?

Correct Answer: Option A — duration of the exposure

Sensitized colorimetric H2S detector tapes react based on both gas concentration and the cumulative duration of exposure, where longer exposure to a specific concentration deepens the spot coloration proportionally.