Step-by-step explanation:
It is known that the relation between electric field and potential difference between the plates of a parallel plate capacitor is as follows.
E =

So, differentiating this on both the sides with respect o time as follows.

Hence, rate of electric field changes between the plates of parallel plate capacitor as follows.

=

=
V/ms
Thus, we can conclude that the rate at which the electric field changes between the round plates of a capacitor is
V/ms.