In Fig. 29.23 the capacitor plates have area 5.00 cm2 and separation 2.00 mm. The plates are in vacuum. The charging current $i_C$ has a $constant$ value of 1.80 mA. At $t$ = 0 the charge on the plates is zero. (a) Calculate the charge on the plates, the electric field between the plates, and the potential difference between the plates when $t =$ 0.500 $\mu$s. (b) Calculate $dE/dt$, the time rate of change of the electric field between the plates. Does $dE/dt$ vary in time? (c) Calculate the displacement current density $j_D$ between the plates, and from this the total displacement current $i_D$. How do $i_C$ and $i_D$ compare?