The SI unit of amplitude depends on the physical quantity being described.
In the context of waves, such as sound waves or electromagnetic waves, amplitude refers to the maximum displacement or magnitude of the oscillation. The SI unit of amplitude for such waves is meters (m). For example, in the case of a sound wave, the amplitude represents the maximum displacement of air particles from their equilibrium position as the wave propagates.
However, amplitude can also represent other physical quantities in different contexts. For instance, in the field of vibrations and oscillations, amplitude can represent the maximum displacement of an object from its equilibrium position. In this case, the SI unit of amplitude would also be meters (m).
It's worth noting that the amplitude of certain quantities, such as electric current or voltage, is often expressed in different units depending on the specific application or context.