Moving Charges And Magnetism

The magnetic field at a point \(\mathrm{P}\) situated at perpendicular distance '\(R\)' from a long straight wire carrying a current of \(12 \mathrm{~A}\) is \(3 \times 10^{-5} \mathrm{~Wb} / \mathrm{m}^2\). The value of '\(\mathrm{R}\)' in \(\mathrm{mm}\) is \(\left[\mu_0=4 \pi \times 10^{-7} \mathrm{~Wb} / \mathrm{Am}\right]\)