Often, we encounter situations where more than one current is involved, each producing its own magnetic field. Suppose, we have two wires carrying currents with \(\vec B_1\) be the magnetic field of wire 1 and \(\vec B_2\) be the magnetic field of wire 2. The net magnetic field will be just a vector sum of the two.
\begin{equation}
\vec B = \vec B_1 + \vec B_2.\tag{2.15}
\end{equation}
This is called superposition principle of magnetic field.
