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…

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