*Question E9G11:
In what units are the wavelength scales on a Smith chart calibrated?*  

*Correct Answer is  B: In fractions of transmission line electrical wavelength*  

### AI Response: (may contain errors)  

The correct answer is **B: In fractions of transmission line electrical wavelength**.

### Explanation:

1. **Why the correct answer is correct:**
   - The Smith chart is a graphical tool used primarily for solving problems with transmission lines and matching circuits. It is calibrated in terms of the electrical wavelength along the transmission line. This means that the scales on the Smith chart represent distances as fractions of the wavelength of the signal traveling through the transmission line. This is crucial for understanding how impedance changes along the line.

2. **Why the other choices are incorrect:**
   - **A: In fractions of transmission line electrical frequency**: Frequency is not directly represented on the Smith chart. The chart deals with impedance and reflection coefficients, which are functions of wavelength, not frequency.
   - **C: In fractions of antenna electrical wavelength**: The Smith chart is not used for antenna wavelengths directly. It is specifically designed for transmission line analysis.
   - **D: In fractions of antenna electrical frequency**: Similar to choice A, frequency is not the parameter used for calibration on a Smith chart. The chart is concerned with wavelength, not frequency.

### Useful Concepts:

- **Wavelength ($\lambda$)**: The distance over which the wave's shape repeats. It is inversely related to frequency ($f$) by the formula:
  $$ \lambda = \frac{v}{f} $$
  where $v$ is the velocity of the wave in the medium.

- **Smith Chart Calibration**: The outer circle of the Smith chart is often marked in fractions of a wavelength, such as $\lambda/8$, $\lambda/4$, $\lambda/2$, etc., which helps in visualizing how impedance transforms along a transmission line.

Understanding these concepts will help you effectively use the Smith chart for analyzing and designing RF circuits.