* Meters (m): The standard unit of length in the International System of Units (SI).
* Nanometers (nm): Commonly used for measuring wavelengths of light, including visible light. 1 nm = 10⁻⁹ m.
* Micrometers (µm): Used for measuring wavelengths of infrared radiation. 1 µm = 10⁻⁶ m.
* Angstroms (Å): Historically used for measuring atomic and molecular sizes, and sometimes used for wavelengths of X-rays. 1 Å = 10⁻¹⁰ m.
The specific unit used depends on the size of the wavelength being measured. For example, visible light has wavelengths in the hundreds of nanometers, while radio waves have wavelengths of meters or even kilometers.
