Answer:
Electromechanical waves are defined as the waves which resulting from the interaction of magnetic fields, and oscillating electric. Some examples of these electromechanical wave are infrared, microwave, ultraviolet, visible, etc.
When these waves are arranged in the order of increasing wavelength then it's called an electromagnetic spectrum, and
spectral regions in order of increasing wavelength, we will get is:
Ultraviolet<visible<infrared<microwave.