This is the distribution of power over a frequency range, often described using Power Spectral Density (PSD) . It helps engineers see where the "strength" of a signal lies. Light and Imaging:
The specific mix of wavelengths in a light source. This is used in astronomy to determine what stars are made of or how fast they are moving.
The ability of a sensor (like a camera) to distinguish between different wavelengths of light, such as infrared or ultraviolet, beyond what the human eye can see.