*Question G9A05:
How does the attenuation of coaxial cable change with increasing frequency?*  

*Correct Answer is  B: Attenuation increases*  

### AI Response: (may contain errors)  

The correct answer to the question about the attenuation of coaxial cable with increasing frequency is:

**B: Attenuation increases.**

### Explanation:

1. **Why the correct answer is correct:**
   - As the frequency of the signal transmitted through coaxial cable increases, the attenuation (or loss of signal strength) also increases. This is primarily due to two factors:
     - **Dielectric Loss:** At higher frequencies, the dielectric material in the cable absorbs more energy, leading to greater losses.
     - **Skin Effect:** Higher frequencies cause the current to flow primarily on the surface of the conductor, which increases the effective resistance and thus the attenuation.

2. **Why the other choices are incorrect:**
   - **A: Attenuation is independent of frequency:** This is incorrect because attenuation is indeed affected by frequency, as explained above.
   - **C: Attenuation decreases:** This is also incorrect. Attenuation does not decrease with frequency; it increases due to the reasons mentioned.
   - **D: Attenuation follows Marconi’s Law of Attenuation:** While Marconi's Law relates to radio wave propagation, it does not specifically describe the behavior of coaxial cable attenuation with frequency. Therefore, this choice is misleading.

### Useful Formulas or Rules of Thumb:
- A common rule of thumb is that coaxial cable attenuation can be approximated in decibels (dB) per 100 feet (or meters) and typically increases logarithmically with frequency. 

For example, a typical coaxial cable might have an attenuation of:
$$
A(f) = A_0 + k \cdot f
$$
where:
- $A(f)$ = attenuation at frequency $f$
- $A_0$ = base attenuation at a reference frequency
- $k$ = frequency-dependent increase in attenuation

This illustrates that as frequency ($f$) increases, the attenuation ($A(f)$) also increases.