Wavelength and amplitude are two distinct properties of a wave:
Wavelength: Wavelength is a measure of the distance between two consecutive points in a wave that are in the same phase. It represents the spatial period of the wave and is usually denoted by the symbol λ (lambda). In other words, it is the distance over which the wave completes one full cycle of its oscillation. For example, in a transverse wave, such as a water wave or a light wave, the wavelength is the distance between two adjacent peaks or two adjacent troughs. In a longitudinal wave, such as a sound wave, the wavelength is the distance between two consecutive compressions or rarefactions. Wavelength is typically measured in units such as meters (m) or nanometers (nm).
Amplitude: Amplitude refers to the maximum displacement or magnitude of the wave from its equilibrium or rest position. It measures the intensity or strength of the wave. In other words, amplitude represents the maximum extent to which the particles in the medium are displaced from their equilibrium positions as the wave passes through. In a transverse wave, the amplitude is the distance between the equilibrium position and the peak (or trough). In a longitudinal wave, it corresponds to the maximum compression or rarefaction. Amplitude is typically measured in units such as meters (m) or volts (V) depending on the type of wave.
To summarize, wavelength describes the spatial characteristics of a wave, representing the distance between consecutive points of the same phase, while amplitude characterizes the magnitude or intensity of the wave, representing the maximum displacement or magnitude of the oscillation.