Which of these actions is considered unsafe with regard to radiation safety?

Using the device without supervision is considered unsafe with regard to radiation safety because operating a nuclear gauge demands a clear understanding of its functionality, potential hazards, and the appropriate safety protocols. Supervision typically comes from a trained professional who can ensure that safety measures are being followed and that anyone operating the device is aware of the risks associated with radiation exposure. The presence of a knowledgeable supervisor helps to prevent accidents and mismanagement of the equipment, which can lead to serious consequences, including both radiation exposure and environmental contamination.

In contrast, wearing protective gear during operation, regularly testing the device for functionality, and following proper disposal procedures are all practices that enhance safety and effectively mitigate risks associated with radiation. Protective gear minimizes exposure, routine testing ensures the device operates safely, and proper disposal prevents contamination and protects the environment. Together, these practices underscore a commitment to safety within the field of radiation handling and measurement.