Rank these electromagnetic waves on the basis of their speed (in vacuum). Rank from fastest to slowest:

Rank these electromagnetic waves on the basis of their speed (in vacuum). Rank from fastest to slowest:

a. yellow light

b. green lights

c. x ray

d. FM radio wave

e. AM radio wave

f. infrared light

Answer: The correct ranking is c, a, b and d.

All electromagnetic waves in a vacuum, that is, light of all frequency travel at the same speed which is the speed of light (3 ×10 8m/s). Electromagnetic wave does not lose their speed it has whatever the frequency and the wavelength are. However, depending on the decision made with regard to ranking them as dependent of the frequency or, on the contrary, the wavelength of the waves, the preliminary ranking may look like the following:

As seen, among all the instruments, X-rays have the highest frequency, and the least wavelength while the yellow light and then the green light and at last the FM radio waves have moderate values of both the frequency, as well as the wavelength. It should be noted that all the electromagnetic waves change their speeds by the kind of media through which they pass, the ones that pass through vacuum change speed in the speed only associated with light.