Which electromagnetic waves have the highest frequency?
Gamma rays have the highest frequency.
Example value for gamma frequency:
There are seven regions in the electromagnetic spectrum which in order of lowest to highest frequency are:
Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays.
The regions do blend into each other, so there is not a sharp transition between radio waves and microwaves for example. Also at the high frequency end the regions of x-rays and gamma rays overlap for a considerable part of the spectrum. But we still distinguish between the two because their methods of production are different (x-rays by decelerating electrons and gamma rays by nuclear decay).
Wavelength is inversely proportional to frequency, therefore radio waves have the longest wavelengths and gamma rays have the shortest. Example value for gamma wavelength: