Point particle of point charges cannot be maintained in an equilibrium configuration solely by the electrostatic interaction of the charges. In quantum mechanics, there is a distinction between an elementary particle (also called "point particle") and a composite particle. An elementary particle, such as an electron, quark, or photon, is a particle with no internal structure. Whereas a composite particle, such as a proton or neutron, has an internal structure (see figure). However, neither elementary nor composite particles are spatially localized, because of the Heisenberg uncertainty principle. The particle wavepacket always occupies a nonzero volume. For example, see atomic orbital: The electron
Ida (given name) may refer to: Ida (given name) Ida is a given name occurring independently in several cultures. In Germany, Ida is a female name derived from a Germanic word "id", meaning "labor, work". Alternately, it may be related to the name of the Old Norse goddess "Iðunn". Ida also occurs as an anglicisation of the Irish girl's given name Íde. Ida is a currently popular name in the Nordic countries and is among the top 10 names given to girls born in 2013 in Denmark. It was among the top 20 names for newborn girls in Norway in 2013 and among