There is a circular electrode having radius of 0.15m. There is a uniform oscillating magnetic field B cos (wt) with B = 0.001T and w = 2*pi*3000Hz perpendicular to the electrode. If we wish for to coat the electrode having a layer of graphite (resistivity = 7.5 x 10^-6), how thin should the graphite be if we wish for to keep the heating beneath 0.1W?