Final answer:
Three types of alarms and signals to warn of NBC hazards include audible alarms like sirens, visual alarms such as flashing lights, and chemical alarms with specialized sensors. Geiger counters, which click when detecting radiation, can act as an audible alarm.
Step-by-step explanation:
Alarms and signals are essential for conveying warnings of potential NBC (nuclear, biological, and chemical) hazards. The three types of alarms and signals for such hazards include:
- Audible alarms: these could be sirens or horns that signal the presence of a hazard. It might be a continuous tone or a pattern of sounds that convey a specific warning.
- Visual alarms: these include flashing lights, color-coded warnings, or even banners or flags used to indicate different levels of threat or areas of contamination.
- Chemical alarms: these alarms detect the presence of chemical agents through specialized sensors and can trigger auditory or visual signals to warn of the danger.
Devices such as Geiger counters, scintillators, and dosimeters are used to measure radiation levels and alert to the presence of radioactive materials, falling under the category of audible alarms when producing a clicking sound upon detection of ionizing radiation. To protect from radiation exposure, one can use shielding with dense materials such as lead, increase distance from the source, and minimize exposure time.