Final answer:
When the amplitude of a wave increases, the energy of the wave increases. While amplitude and frequency are independent of each other, frequency decreases as the period increases. Amplitude typically decreases with distance due to damping.
Step-by-step explanation:
In the context of waves, when the amplitude of the wave increases, the energy of the wave also increases. Therefore, the correct answer to the question is c) The energy increases.
It's important to note that while amplitude and energy are directly related, the amplitude of a wave is independent of its frequency. However, when the period of a wave increases, its frequency decreases as they are inversely related. Thus, the answer to this part would be a) Its frequency decreases.
Regarding the amplitude and the distance from the source, it is typical for the amplitude of a sound wave to decrease as it gets further from its source. This reduction is often due to the energy of the wave spreading over a larger area and is known as damping, where over time, the energy dissipates and the amplitude gradually reduces to zero.