Final answer:
Waves that are shorter than ultraviolet and much smaller than the wavelength of visible light are called X-rays, which are part of the electromagnetic spectrum that includes gamma rays, ultraviolet, visible light, infrared, microwaves, and radio waves.
Step-by-step explanation:
Waves that are shorter than ultraviolet and about one-thousandth the wavelength of visible light are known as X-rays. The spectrum of electromagnetic radiation includes a range of wavelengths with specific names in the order of increasing wavelength: gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves, and radio waves. As electromagnetic radiation with wavelengths between 0.01 nanometer and 20 nanometers, X-rays are more energetic than visible light and have the capacity to penetrate soft tissues but not bones, making them very useful in medical imaging.