*Question G9B12:
What is the approximate length for a 1/4 wave monopole antenna cut for 28.5 MHz?*  

*Correct Answer is  A: 8 feet*  

### AI Response: (may contain errors)  

To determine the approximate length of a 1/4 wave monopole antenna for a given frequency, you can use the formula:

$$
L = \frac{234}{f}
$$

where:
- $L$ is the length of the antenna in feet.
- $f$ is the frequency in megahertz (MHz).

For a frequency of 28.5 MHz, the calculation is:

$$
L = \frac{234}{28.5} \approx 8.21 \text{ feet}
$$

This calculation shows that the approximate length is 8 feet, which matches choice A.

### Explanation of Choices:
- **A: 8 feet**  
  This is the correct answer because the calculated length of approximately 8.21 feet rounds to 8 feet.

- **B: 11 feet**  
  This is incorrect because it is longer than the calculated length for 28.5 MHz.

- **C: 16 feet**  
  This is incorrect because it is significantly longer than the calculated length for 28.5 MHz.

- **D: 21 feet**  
  This is incorrect because it is much longer than the calculated length for 28.5 MHz.

### Key Points:
- The formula $\frac{234}{f}$ is a rule of thumb for calculating the length of a 1/4 wave monopole antenna in feet.
- The correct length for 28.5 MHz is approximately 8 feet, making choice A the correct answer.