*Question G9A10:
What standing wave ratio results from connecting a 50-ohm feed line to a 10-ohm resistive load?*  

*Correct Answer is  D: 5:1*  

### AI Response: (may contain errors)  

To determine the standing wave ratio (SWR) when connecting a 50-ohm feed line to a 10-ohm resistive load, we use the formula for SWR:

$$
\text{SWR} = \frac{R_L}{R_0} \quad \text{if } R_L > R_0
$$

or

$$
\text{SWR} = \frac{R_0}{R_L} \quad \text{if } R_0 > R_L
$$

where:
- $R_0$ is the characteristic impedance of the feed line (50 ohms in this case).
- $R_L$ is the load impedance (10 ohms in this case).

Since $R_0 > R_L$, we use the second formula:

$$
\text{SWR} = \frac{50}{10} = 5:1
$$

### Explanation:
1. **Correct Answer (5:1):**  
   - The calculation shows that the SWR is 5:1 when a 50-ohm feed line is connected to a 10-ohm load. This indicates a mismatch, as the SWR is greater than 1:1.

2. **Incorrect Choices:**
   - **2:1 (Choice A):** This would imply a smaller mismatch, which is not the case here.
   - **1:2 (Choice B):** SWR is always expressed with the larger number first, so 1:2 is not a valid SWR expression.
   - **1:5 (Choice C):** Similar to 1:2, this is not a valid SWR expression because the larger number should be first.

### Key Points:
- SWR is a measure of impedance matching between the feed line and the load.
- A perfect match is 1:1, and any deviation indicates a mismatch.
- The larger the SWR, the greater the mismatch and potential for reflected power.