What is the principal difference between a radio wave and visible light? Between visible light and an X-ray? Radio waves have a lower frequency and longer wavelength than visible light waves. Light waves have a lower frequency and longer wavelength than X-rays. Radio waves have a lower frequency and shorter wavelength than visible light waves. Light waves have a higher frequency and longer wavelength than X-rays. Radio waves have a lower frequency and longer wavelength than visible light waves. Light waves have a higher frequency and shorter wavelength than X-rays. Radio waves have a higher frequency and longer wavelength than visible light waves. Light waves have a higher frequency and longer wavelength than X-rays