Final answer:
The maximum permissible radiation dose for an individual in an unrestricted area in one hour is 0.002 rems. This limit helps prevent significant health risks from radiation exposure.
The rem unit measures radiation dose based on biological effects.
Step-by-step explanation:
The question posed pertains to the maximum permissible radiation exposure limit for an individual in an unrestricted area over the span of one hour.
Based on standard safety guidelines, the correct answer is that no individual member of the public may receive more than 0.002 rems in any one hour in an unrestricted area, which means the third option, 0.002 rems, is correct. This limit is established to ensure public safety and minimize the risk of radiation-induced health effects.
An understanding of the unit rem, which stands for roentgen equivalent man, is important for this context. It is a unit of radiation dosage that takes into account the biological effects of radiation. This means that regardless of the type of radiation, the rem unit accounts for the potential tissue damage inflicted on humans.
When we talk about the risks of radiation exposure, studies have shown that a dose of 1 rem increases the risk of dying from radiation-induced cancer by 0.03 percent over a lifetime.
By contrast, a much higher dose, such as 100 rem, which is equivalent to 1 sievert (Sv) and was the average dose received by survivors of the Hiroshima and Nagasaki bombings, leads to a significant increase in the observable risk at 3 percent. These statistics demonstrate why stringent regulations on radiation exposure are crucial for protecting public health.