ARRL Technician Practice Exam

Why is duty cycle considered when determining safe RF radiation exposure levels?

1. It determines the transmitter's power limitations

2. It affects the average exposure of people to radiation

3. It regulates the audio frequency used

4. It influences the type of antennas used

The correct answer is: It affects the average exposure of people to radiation

Duty cycle is a critical factor in assessing safe RF radiation exposure levels because it quantifies the proportion of time a transmitter is active versus inactive. When a radio frequency device is in operation, it emits RF energy, and the amount of exposure a person might receive depends not only on the power of the transmitter but also on how long it transmits over a given period. B. The concept of duty cycle is essential in evaluating the average exposure since it's not just about knowing how much power is being radiated at any given moment, but rather how frequently and for how long that power is being transmitted. A high duty cycle means that the transmitter is on more often, leading to higher average exposure levels, while a lower duty cycle allows for longer off periods, resulting in lower average exposure. Regulatory guidelines for RF exposure often account for both power levels and the duty cycle to ensure that individuals are not exposed to harmful levels of RF radiation over time. Understanding this relationship is crucial for operators and engineers to ensure compliance with safety standards and to minimize any potential health risks associated with RF exposure.