Which color of light has the longest wavelength?

Light is made up of electromagnetic waves that travel in varying wavelengths, which we perceive as different colors. The spectrum of visible light ranges from violet at the shortest wavelengths to red at the longest wavelengths.

Red light has a wavelength that typically varies from about 620 to 750 nanometers, making it longer than the wavelengths of green (which ranges from approximately 495 to 570 nm), blue (which ranges from about 450 to 495 nm), and yellow (which spans roughly 570 to 590 nm).

Therefore, red light, having the longest wavelength in the visible spectrum, is the correct choice in this context. This concept is crucial in understanding how we categorize light and its various wavelengths, particularly in fields like physics and optics where the properties of light are fundamental.