What describes the amplitude of a wave?

The amplitude of a wave is defined as the maximum distance from the rest position to either the crest (the highest point) or the trough (the lowest point) of the wave. This characteristic describes how far the wave oscillates from its undisturbed position, which directly relates to the energy the wave carries. A greater amplitude indicates more energy, while a smaller amplitude suggests less energy.

Understanding amplitude is critical in various contexts, such as sound waves, where a higher amplitude corresponds to louder sounds, or in electromagnetic waves, where it might relate to the intensity of light. The other choices describe different aspects of wave behavior: the distance between the peaks refers to wavelength, the time for one cycle describes the period, and the speed pertains to how fast the wave propagates through a medium.