A sphere of capacitance 100 pF is charged to a potential of 100 V. Another identical uncharged metal sphere is brought in contact with the charged…

A sphere of capacitance $\displaystyle 100$ pF is charged to a potential of $\displaystyle 100$ V. Another identical uncharged metal sphere is brought in contact with the charged sphere, then the change in the total energy stored on these spheres, when they touch is $\displaystyle \alpha \times 10^{-7} \mathrm{~J}$. The value of $\displaystyle \alpha$ is $\displaystyle \_\_\_\_$. (combined capacitance of spheres is $\displaystyle 200$ pF )