The magnetic field between the plates of a capacitor when r > R is given by:

$\frac{\mu_0 I_D r}{2 \pi R^2}$ $\frac{\mu_0 I_D}{2 \pi R}$ $\frac{\mu_0 I_D}{2 \pi r}$ 'kwU

$\frac{\mu_0 I_D}{2 \pi r}$

According to Ampere's law, when r > R B = $\frac{\mu_0 I_D}{2 \pi r}$