What color of light has the highest velocity?

Answer 1

Red has the greatest velocity in mediums such as glass and water, that is why it is refracted least. The index of refraction, n is the ratio of the light's speed in vacuum over its speed in a medium. ie. n=c/v.

For example, light has an index of refraction of 1.5 in glass. This means n = 1.5 = 3/2 = c/v. This means that light travels at about 2/3 rds the speed in glass as it does in empty space. Here are some typical numbers for a glass.

Color -- Wavelength --- n ------- c/v ---- v/c

Blue ------- 434 nm ---- 1.528 ---- 1.528 ---- .654

Yellow ---- 550 nm ---- 1.517 ---- 1.517 ---- .659

Red -------- 700 nm ---- 1.510 ---- 1.510 ---- .662 This makes for a difference in speed of about 1.2 %

Answer 2

All colors of light travel at the same speed in a vacuum, which is approximately 299,792 kilometers per second. This speed is known as the speed of light.