How is amplitude defined in the context of waves?

In the context of waves, amplitude is defined as the height from the equilibrium line to either the crest (the highest point of the wave) or the trough (the lowest point of the wave). This measurement represents the energy of the wave; a larger amplitude indicates higher energy and a more intense wave.

For instance, in sound waves, a greater amplitude corresponds to a louder sound, while in light waves, it might indicate a brighter light. Understanding amplitude is crucial for interpreting wave properties in various contexts, such as sound, light, and water waves.

Other options refer to different characteristics of waves. The distance from crest to crest specifies the wavelength. The speed of a wave pertains to how fast it travels through a medium. The number of waves passing a point per second describes the frequency, which, along with amplitude and wavelength, helps to characterize the nature of the wave.