Which of the following colors of visible light has the longest wavelength?

• A. Violet
• B. Red
• C. Blue
• D. Green

Answer: (B)

Verified step by step guidance

1. Recall that visible light is part of the electromagnetic spectrum, and different colors correspond to different wavelengths.
2. Understand that the visible spectrum ranges approximately from 400 nm (violet) to 700 nm (red) in wavelength.
3. Identify the order of colors by wavelength from shortest to longest: violet, blue, green, yellow, orange, red.
4. Recognize that among the given options (violet, blue, green, red), red light has the longest wavelength.
5. Conclude that red light has the longest wavelength because it is at the lower-energy, longer-wavelength end of the visible spectrum.