Which of the following electromagnetic waves has the shortest wavelength?
a. visible light waves
b. ultraviolet waves
c. microwaves
d. infrared waves

The human eye sees radio waves with a very short wavelength, which is another way of saying high-frequency waves. The word "ultra" should queue you in that ultraviolet waves are higher frequency than just violet waves. Violet is sorta purplish or blueish, which is the highest frequency or "color" that our eyes can see. So ultraviolet is higher frequency than visible light, which is the same thing as "color." On the other hand, red is the lowest frequency or highest wavelength that our eyes can see. And "Infra" means lower than red, so, infrared waves are "colors" or frequencies, smaller than visible light. To determine where microwaves fall under look up "Electromagnetic Spectrum." Good luck!