Moving Charges And Magnetism

Two parallel wires of equal lengths are separated by a distance of \(3 \mathrm{~m}\) from each other. The currents flowing through \(1^{\text {st }}\) and \(2^{\text {nd }}\) wire is \(3 \mathrm{~A}\) and 4.5 A respectively in opposite directions. The resultant magnetic field at mid point between the wires \(\left(\mu_0=\right.\) permeability of free space)