Which characteristic of light does not describe the 400-1000 nm wavelength?

Monochromatic light refers to light that consists of a single wavelength or color. The range of wavelengths from 400 to 1000 nm encompasses visible light and extends into the infrared spectrum, which means it actually includes multiple wavelengths of light. Therefore, this range cannot be characterized as monochromatic since it is made up of various wavelengths.

In contrast, the terms broadband and polychromatic accurately describe the 400-1000 nm wavelength range, as both refer to the presence of a wide spectrum of wavelengths. Non-coherent light is also applicable here because it typically refers to light sources that emit light waves of different phases and frequencies; the 400-1000 nm spectrum, which includes diverse wavelengths, fits this definition as well. Thus, the characteristic that does not apply to this wavelength range is indeed monochromatic.