What cabin altitude triggers a warning light?

The cabin altitude that triggers a warning light is typically set at 10,000 feet. This altitude serves as a critical threshold because it is where physiological effects of hypoxia (low oxygen levels) can begin to affect passengers and crew if exposure is prolonged. Warning systems are designed to alert the flight crew if cabin pressure is not maintained within safe limits to ensure the well-being of those on board.

While the incorrect options may reference altitudes that are near this threshold, they do not align with the standard safety measures implemented in aviation regarding cabin altitude warnings. The establishment of 10,000 feet as the threshold helps promote timely corrective action by the flight crew.