Which is faster: a red photon moving through a vacuum or a blue photon moving through a vacuum?

1 Answer
Michael
Dec 4, 2015

They have the same speed.

Explanation:

The speed is given by:

#c=fxxlambda#

A red photon has a longer wavelength ( #~700"nm"# ) than a blue photon (#~400"nm"#). Consequently it has a lower frequency as does the blue photon have a higher frequency.

The speed of light #c# remains constant at a value of #3xx10^(8)"m/s"#

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