Monopole

The monopole is the first term (\(n=0\)) of the multipole expansion. For a charge source of total charge \(Q\),

\[ V(\boldsymbol r) = \frac{1}{4\pi\epsilon_0} \frac{Q}{r} \]

This equation mirrors the exact potential for a point charge at distance \(d=r\) where we center the origin at the point charge.