*Question G9A09:
What standing wave ratio results from connecting a 50-ohm feed line to a 200-ohm resistive load?*  

*Correct Answer is  A: 4:1*  

### AI Response: (may contain errors)  

To determine the standing wave ratio (SWR) when connecting a 50-ohm feed line to a 200-ohm resistive load, we can use the formula for SWR:

$$
SWR = \frac{Z_L + Z_0}{Z_L - Z_0}
$$

where:
- $Z_L$ = load impedance (200 ohms)
- $Z_0$ = characteristic impedance of the feed line (50 ohms)

Substituting the values into the formula:

$$
SWR = \frac{200 + 50}{200 - 50} = \frac{250}{150} = \frac{5}{3} \approx 1.67
$$

However, this is not the correct approach for this specific question. Instead, we can use the following simplified relationship for SWR when the load impedance is greater than the feed line impedance:

$$
SWR = \frac{Z_L}{Z_0}
$$

Substituting the values:

$$
SWR = \frac{200}{50} = 4
$$

Thus, the SWR is 4:1.

### Explanation of the Correct Answer:
- **Correct Answer (A: 4:1)**: The SWR of 4:1 indicates that the load impedance (200 ohms) is four times the feed line impedance (50 ohms). This means that there is a significant mismatch, leading to a higher SWR.

### Explanation of Incorrect Choices:
- **B: 1:4**: This would imply that the load impedance is one-fourth of the feed line impedance, which is not the case here (200 ohms vs. 50 ohms).
- **C: 2:1**: This would suggest that the load impedance is twice the feed line impedance, which again does not apply since 200 ohms is not twice 50 ohms.
- **D: 1:2**: This would indicate that the load impedance is half of the feed line impedance, which is incorrect for the given values.

### Summary:
- The correct SWR is calculated using the ratio of the load impedance to the feed line impedance when the load is greater than the feed line.
- The formula used is:

$$
SWR = \frac{Z_L}{Z_0}
$$

This helps in understanding the impedance mismatch and its effect on the standing wave ratio.