*Question E1A07:
[97.313(k)] What is the maximum power permitted on the 2200-meter band?*  

*Correct Answer is  C: 1 watt EIRP (equivalent isotropic radiated power)*  

### AI Response: (may contain errors)  

The correct answer to the question about the maximum power permitted on the 2200-meter band is:

**C: 1 watt EIRP (equivalent isotropic radiated power)**

### Explanation of the Correct Answer:
- The 2200-meter band is a very low frequency (VLF) band, and regulations set by the FCC limit the maximum power to 1 watt EIRP. 
- EIRP takes into account both the transmitter power and the gain of the antenna, providing a measure of the effective power radiated in a specific direction.

### Why the Other Choices are Incorrect:
- **A: 50 watts PEP**  
  This option is incorrect because the FCC regulations specifically limit the power to 1 watt EIRP for the 2200-meter band, not peak envelope power (PEP).
  
- **B: 100 watts PEP**  
  Similar to option A, this is incorrect for the same reason. The limit is not based on PEP but rather on EIRP, which is much lower.
  
- **D: 5 watts EIRP**  
  This option is also incorrect because it exceeds the maximum allowed EIRP for the 2200-meter band, which is strictly limited to 1 watt.

### Useful Formulas and Rules of Thumb:
- **EIRP Calculation**:  
  To calculate EIRP, you can use the formula:  
  $$EIRP = P_T \times G_A$$  
  where:
  - $P_T$ = transmitter power in watts
  - $G_A$ = antenna gain (linear)

- **Understanding EIRP**:  
  EIRP is a crucial concept in amateur radio as it helps ensure compliance with power limits while considering the gain of antennas. Always check the specific band regulations for power limits, as they can vary significantly between bands. 

This knowledge is essential for passing the Extra Class exam and for operating within legal limits in amateur radio.