*Question E9F04:
What impedance does a 1/2-wavelength transmission line present to an RF generator when the line is shorted at the far end?*  

*Correct Answer is  B: Very low impedance*  

### AI Response: (may contain errors)  

When dealing with transmission lines, it's important to understand how the length of the line and its termination affect the impedance seen by an RF generator.

### Explanation:

1. **Correct Answer: Very low impedance**

   - A 1/2-wavelength transmission line that is shorted at the far end will present a very low impedance to the RF generator. This is because a 1/2-wavelength line transforms the impedance at its load (in this case, a short, which is 0 ohms) to the same impedance at the input. Therefore, the input impedance is also very low.

2. **Why the other choices are incorrect:**

   - **Choice A: Very high impedance**  
     This would be true for a 1/4-wavelength line shorted at the far end, not a 1/2-wavelength line. A 1/4-wavelength line transforms a short to an open (high impedance).

   - **Choice C: The same as the characteristic impedance of the line**  
     This would be true if the line were terminated in its characteristic impedance, not shorted.

   - **Choice D: The same as the output impedance of the RF generator**  
     The impedance seen by the generator is determined by the transmission line and its termination, not by the generator's output impedance.

### Useful Rule of Thumb:

- **1/2-Wavelength Line Transformation:**  
  A 1/2-wavelength transmission line repeats the impedance of its load at the input. If the load is a short (0 ohms), the input impedance is also a short (very low impedance).

Understanding these principles helps in analyzing transmission line behavior and predicting how they will interact with RF generators.