If a wave's amplitude is low, what does this imply?

When a wave's amplitude is low, it indicates that the energy carried by the wave is also low. Amplitude refers to the maximum displacement of points on a wave from its rest position, which is directly related to the energy of the wave. In many types of waves, such as sound and electromagnetic waves, a higher amplitude means more energy. Therefore, a wave with low amplitude cannot transport significant energy, making option A the correct choice.

The other options do not correctly correlate with low amplitude. For example, wave speed is governed by the medium through which it travels rather than its amplitude. Wavelength and frequency are also independent of amplitude in a wave, so having a low amplitude does not necessarily indicate anything about these properties. This reinforces the understanding that amplitude is a measure of energy, making the first choice the most accurate in this context.