Microwave frequency bands in the increasing wavelengths (decreasing frequencies), which are Ku band, X band, C band, S band, L band, respectively King Xerxes Can Seduce Lovely princesses

Sequence of colors in a rainbow or visible spectrum: red, orange, yellow, green, blue, indigo, violet "Richard Of York Gave Battle In Vain" "Riding On Your Granny's Bike Is Vile"

The speed of light in meters per second: 299,792,458 m/s "We guarantee certainty, clearly referring to this light mnemonic" through the number of letters in each word

Radio waves, microwaves, infrared radiation, visible light, ultraviolet, X-rays, gamma Raging Martians invaded Venus using X-ray guns