Show that the magnetic field B at a point in between the plates of a parallel plate capacitor during charging is `(mu_(0)epsilon_(0)r)/(2) (dE)/(dt)` (symbols having usual meaing). ,

Explanation

Let `I_D` be the displacement current in the region between two plates
of parallel plate capacitor, Fig. The magnetic field
induction at a point in a region between two plates of capacitor at
`abotr` distance r from the axis of plate is
`B=(mu_0)/(4pi) (2I_D)/r=(mu_0)/(2pir) I_D=(mu_0)/(2pir)xxin_0 (d phi_E)/(dt) [ :' I_D=in_0 (dphi_E)/(dt)]`
`=(mu_0in_0)/(2pir) d/(dt) (Epir^2)=(mu_0in_0)/(2pir) pir^2 (dE)/(dt) =(mu_0in_0 r)/2 (dE)/(dt) ( :' phi_E=Epir^2)`