Final answer:
Gamma Rays have the highest energy per photon in the electromagnetic spectrum, due to their high frequency and short wavelength.
Step-by-step explanation:
According to the electromagnetic spectrum, the part that has the most energy per photon is Gamma Rays. The electromagnetic spectrum is comprised of all forms of electromagnetic radiation, ranging from those with the longest wavelength, like radio waves, to those with the shortest wavelength, such as gamma rays. Gamma rays have the highest frequency and, consequently, the highest energy, making them the most energetic part of the spectrum, followed by X-rays, ultraviolet, visible light, infrared, microwaves, and, finally, radio waves. It's important to understand that the energy of electromagnetic radiation is directly proportional to its frequency and inversely proportional to its wavelength.