A parallel plate capacitor with circular plates of radius 1 m has a capacitance of 1 nF. ?At t=0, it is connected for charging in series with a resitor R=1M `Omega` across a 2V battery (Fig. 8.3) calculate the magnetic field at a point P. halfway between the centre and the periphery of the plates after l=`10^(-3)`s. (The charge on the capacitor at time l is `q(l)=CV` [1-exp(-t/r)]. where the time constant r is equal to CR.)