1. The problem statement, all variables and given/known data A parallel plate air-filled capacitor is being charged as in figure. The circular plates have a radius of 4.0 cm, and at a particular instant the conduction current in the wires is .280 A. A. What is the displacement current density (jD) in the air space between the plates? B. What is the rate at which the electric field between the plates is changing? C. What is the induced magnetic field between the plates at a distance of 2.0 cm from the axis? D. What is the induced magnetic field between the plates at a distance of 1.0 cm from the axis? 2. Relevant equations an image is attached 3. The attempt at a solution This is my solution as is... A. i = .280 A r = 4cm (.04m) n = 3.14 jD=i/nr^2 (thats n*r squared) =.28/3.14*.04^2 = 55.73 A B. dE/dt=jD/ [tex]\epsilon[/tex] (permitivitty constant) = 55.73/8.85*10^-12 = 6.3*10^-12 N/Cs C. B= ur/2nR^2 *i (u = mu) = (1.256*10^-6)(.04m)/2(3.14)(.02*.02) = 2*10^-5 (.28) = 5.6*10^-6 D. B=ur/2nR^2 (i) =(1.256*10^-6)(.04)/2(3.14)(.01*.01) (.28) = 2.24*10^-13 answer a is correct but b, c, and d are not. I have tried this multiple times and cant figure out where im going wrong. Any help would be appreciated.