For 10 points, name this quantity measured in Coulombs, which is positive for a proton.
This quantity is related to isospin by the Gell-Mann-Nishijima equation. The electric flux through a surface is equal to this quantity over permittivity of space according to Gauss's law, and the time derivative of this quantity is current. One experiment involving this quantity balanced the buoyant force with the electric force using oil drops to prove that this quantity is quantized, and that experiment was conducted by Robert Millikan. For 10 points, name this quantity measured in Coulombs, which is positive for a proton.
This quantity is related to isospin by the Gell-Mann-Nishijima equation.
Electric Charge