Physics, Atom, Electron, Nuclear Physics, Quantum Physics.
Bohr. Ground state wavefunction of the Hydrogen atom. a₀ = 0.529E-10 m is the Bohr radius. For example, in the ground state of the Hydrogen atom, instead of orbiting the nucleus exactly at the Bohr radius a₀ = 0.529E-10 m, it has a probability of being found at smaller or larger distances.