Which of the following is an example of a Passive Device?

A passive device in the context of radon measurement does not require power or active electronic components to function; instead, it relies on natural processes to collect measurements. The Alpha Track Detector exemplifies this well. It consists of a small piece of plastic that captures alpha particles emitted by radon gas over time. The detector is later analyzed in a laboratory, where the amount of alpha particles counted can be correlated to the concentration of radon in the environment during the exposure period.

In contrast, devices like Continuous Radon Monitors and Real-time Scintillation Counters are active measurement tools that require electricity to operate and provide immediate readings. These devices continuously measure radon levels through various methods that involve electronic components and data processing. While the Radon Test Sampler may appear to be passive, it typically incorporates methods that may not strictly align with the standard definition of passive devices, utilizing active elements at some stage in the measurement process. Thus, the Alpha Track Detector stands out as the best example of a passive device in this context.