A light wave is a type of electromagnetic wave. Light waves on the electromagnetic spectrum include those that are visible as well as those that are invisible to the human eye.
The average human eye is able to see light with wavelengths between approximately 390 to 700 nanometers, or nm. Violet light is at the top of the spectrum while red is at the bottom. The invisible light found beyond 390 nm is called infrared. The invisible light above 700 nm is called ultraviolet. Radio waves and gamma rays also exist on the electromagnetic spectrum at different wavelengths than both visible and invisible light.