What is one possible warning indicator that x-rays are being produced?

A red light is commonly used as a warning indicator that x-rays are being produced because it signals a potential hazard associated with radiation exposure. The use of a red light provides a clear visual alert to personnel in the vicinity that they should avoid the area or take necessary precautions, as radiation is present. This practice aligns with safety protocols aimed at preventing unintended exposure to ionizing radiation. The choice of red for warning signals is consistent with general safety conventions, where red typically denotes danger or caution.

In contrast, other possible indicators like a green light or a manual switch do not effectively communicate the same level of urgency regarding radiation safety. A green light often signifies that a machine is operational and safe, while a manual switch is used to control the equipment rather than to indicate its operational status or the presence of radiation. A flashing audio signal, while it could be an alert, is less standardized in radiation safety contexts and may not be universally recognized as a radiation warning. Thus, the red light is the most widely accepted and effective choice for signaling when x-rays are actively being produced.