<math>a_0 = {{4\pi\epsilon_0\hbar^2}\over{m_e e^2}}</math>
where:
It has a value of 5.29189379×10-11 m, or about half an angstrom.
... located in Suffolk County, New York. As of the 2000 census, the town had a total population of 5,400. Geography East Farmingdale is located at 40°43'30" North, ...