Wavelength names are generally in lower case:
infrared ultraviolet gamma but X-ray [with a hyphen and a capital X]
Wavelength is often designated by lambda (λ). The SI unit for wavelength is the metre (m) – wavelengths are often expressed in nanometres (nm).
The ultraviolet (UV) region of the electromagnetic spectrum (with wavelengths between visible light and X‑rays) can be subdivided in a number of ways. One of these is based on the interactions of radiation of different wavelengths with biological materials:
UV-A [400–315 nm]
UV-B [315–280 nm]
UV-C [280–100 nm]
[Use a hyphen between the parts of the abbreviation.]