Definition of a Photon. A photon is the quantum of electromagnetic radiation. The term quantum is the smallest elemental unit of a quantity, or the smallest discrete amount of something.
General of the Army(GA) is a five-star general officer and is the second highest possible rank in the United States Army. A special rank of General of the Armies, which ranks above General of the Army, does exist but has only been conferred twice in the history of the Army.
The total number of active duty general officers is capped at 231 for the Army, 62 for the Marine Corps, 198 for the Air Force, and 162 for the Navy. No more than about 25% of a service's active duty general or flag officers may have more than two stars, and statute sets the total number of four-star officers allowed in each service. This is set at 7 four-star Army generals, 9 four-star Air Force generals, 2 four-star Marine generals, and 6 four-star Navy admirals.