What is one way to decrease the external dose rate of radiation?

The correct choice is to reduce the time spent in the area. This principle is grounded in the concept of reducing exposure to radiation. The longer an individual remains in an area where radiation is present, the higher the dose accumulated over time. By minimizing the duration of exposure, the overall radiation dose received is effectively decreased.

This approach is particularly important in environments with higher radiation levels, as it directly impacts the amount of radiation one might absorb. For example, medical professionals working with radiation or individuals near radioactive materials can limit their exposure by spending less time in those areas, thereby maintaining their safety and health.

Other options, such as increasing humidity, wearing heavier clothing, or increasing light levels, do not effectively address the issue of radiation exposure in the same direct manner. Humidity does not inherently reduce radiation levels, while heavier clothing may provide some shielding effect but is not a practical means of minimizing dose in high-radiation environments. Additionally, increasing light levels has no influence on radiation dose rates; rather, it simply affects visibility. Thus, the most effective method listed is to reduce the time spent in an area with radiation.