*Question E0A03:
Over what range of frequencies are the FCC human body RF exposure limits most restrictive?*  

*Correct Answer is  C: 30 - 300 MHz*  

### AI Response: (may contain errors)  

The correct answer to the question about the FCC human body RF exposure limits is:

**C: 30 - 300 MHz**

### Explanation of the Correct Answer:
- The FCC has established that the most restrictive RF exposure limits for human bodies occur in the frequency range of 30 to 300 MHz. This is primarily due to the resonance effects and the way RF energy interacts with biological tissues in this frequency range. At these frequencies, the body can absorb more energy, leading to higher potential exposure levels.

### Why the Other Choices are Incorrect:
- **A: 300 kHz - 3 MHz**
  - This range is generally less restrictive because the RF energy at these lower frequencies tends to penetrate the body less effectively, resulting in lower absorption rates.

- **B: 3 - 30 MHz**
  - While this range does have some restrictions, it is not as critical as the 30 to 300 MHz range. The absorption characteristics of RF energy in this band are not as pronounced as in the higher frequency range.

- **D: 300 - 3000 MHz**
  - Although this range includes microwave frequencies, the exposure limits are not as restrictive as in the 30 to 300 MHz range. At these higher frequencies, the body tends to reflect more RF energy rather than absorb it, leading to different exposure considerations.

### Useful Rules of Thumb:
- RF exposure limits are based on frequency and power density. The higher the frequency, the more critical the exposure limits become, especially in the range of 30 to 300 MHz.
- Always refer to the latest FCC guidelines and standards for specific exposure limits, as they can be updated based on new research and findings.

This understanding is crucial for ensuring safe operation and compliance with FCC regulations regarding RF exposure.