What form of electromagnetic radiation has the shortest wavelength?
The gamma ray has the shortest wavelength (and shortest
period) as well as the highest frequency (and highest energy) of
all forms of electromagnetic radiation.
That's the part of the spectrum that we call "gamma rays".
There is no definite answer to this as we can have shorter and shorter wavelengths from a value which we have assigned to be the shortest wavelength.
However, gamma rays have the shortest wavelength in the
Gamma radiation ;)
The region of the spectrum that we call "gamma rays" has.