Which color has the shortest wavelength in the visible spectrum?

• A. Red
• B. Yellow
• C. Violet
• D. Indigo

Answer: (C)

Colors in the visible spectrum map to wavelengths, with shorter wavelengths toward the violet end and longer wavelengths toward the red end. Among common visible colors, violet sits at the shortest end, roughly 380–450 nanometers. Red is the longest, about 620–750 nm, and yellow sits around 570–590 nm. Indigo, often labeled between blue and violet, is around 445 nm—still longer than violet. Because violet has the smallest wavelength among these options, it is the correct choice.