A parallel plate air capacitor is connected to a battery. The plates are pulled apart at uniform speed v. If x is the se…

A parallel plate air capacitor is connected to a battery. The plates are pulled apart at uniform speed v. If x is the separation between the plates at any instant, then the time rate of change of electrostatic energy of the capacitor is proportional to , where \({x}^{\alpha }\) is ______ .