A time varying potential difference is applied between the plates of a parallel plate capacitor of capacitance \( 2.5 \, \mu\text{F} \). The dielectric constant of the medium between the capacitor plates is \( 1 \). It produces an instantaneous displacement current of \( 0.25 \, \text{mA} \) in the intervening space between the capacitor plates, the magnitude of the rate of change of the potential difference will be __________ \( \text{V}\,\text{s}^{-1} \).
