What color is the equipment used for indicating radioactivity levels?

The equipment used for indicating radioactivity levels is typically associated with the color yellow. This color signals caution and is commonly used to denote areas or equipment that have potential radiation hazards. The use of yellow is part of standard safety practices that communicate danger and the need for immediate awareness when working around radioactive materials.

The options that involve colors like black, red, or white do not represent the standard practices in indicating radioactivity. Each color has specific meanings in safety protocols; for instance, red often signifies fire hazards or stop, while black may not have a universally recognized meaning in this context, and white is often associated with neutral or non-hazardous materials. Yellow's prominence in highlighting areas or equipment related to radioactivity makes it the correct answer for this question.