1 Common rashes include eczema, poison ivy, hives, and athlete's foot. 2  Infections that cause rashes may be fungal, bacterial, parasitic, or viral.  Over-the-counter products may be helpful treatments for many skin rashes.
The conditions under which this process occurs happen in two ways. According to the Cornell Center for... Atoms emit a photon when an electron falls from a high-energy state to a low-energy state. The conditions under which this process occurs happen in two ways. According to the Cornell Center for...
The photon the electron ejects has an amount of energy that corresponds to the energy state it's jumping from to the one it's falling to, we express this energy in terms of that photon's wavelength. So, when an electron falls from n=3 to n=2, it ejects a photon with a wavelength of about 653 nanometers. That photon eventually travels from the nebula to Earth, where it hits your eye or a telescope or whatever, and appears red. This is reason most emission nebulae look red.