The electromagnetic force is one of the four fundamental forces, the
others being the gravitational force, the strong nuclear force, and the
weak interaction. The electromagnetic force dominates on the scale of
atoms and molecules, determining the chemical properties of the elements
and compounds, the chemical reactions occurring on the planet,
and the mechanical, thermal, electrical, and optical properties of materials.
Although the electromagnetic interaction has infinite range like
gravity, in practice the electromagnetic force is negligible on large scales
where gravity dominates instead. This is due to the fact that there are
two sources of electric forces—positive and negative charges—which can
cancel each other, as opposed to the case of gravity, which is only generated
by positive masses. On the larger scales there is no net electric
charge.
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