The amplitude of a wave is the maximum displacement of a point on the wave from its equilibrium (rest) position. It represents the wave's strength or intensity and is measured as the vertical distance from the equilibrium line to the peak (crest) or trough of the wave

. In more practical terms:

• For a transverse wave (like water ripples or a vibrating string), amplitude is the greatest distance the medium moves from its rest position

• For a longitudinal wave (like sound), amplitude is the maximum displacement of particles from their equilibrium position

Amplitude is directly related to the energy carried by the wave-the larger the amplitude, the more energy the wave transfers

. Mathematically, if ymaxy_{max}ymax​ is the maximum displacement and yminy_{min}ymin​ is the minimum displacement, the amplitude AAA can be calculated as:

A=ymax−ymin2A=\frac{y_{max}-y_{min}}{2}A=2ymax​−ymin​​

Amplitude is measured in units of displacement such as meters or centimeters for mechanical waves, and in decibels for sound waves

. In summary, amplitude is the maximum extent of a wave's oscillation measured from its equilibrium position, indicating the wave's intensity or energy