Given,
Two capacitors having values of 10 μF each are connected in parallel.
They are then connected to a 9.0 V battery.
The equivalent capacitance is:
[tex]C=10\mu F+10\mu F=20\mu F[/tex]Thus the energy is equal to,
[tex]\begin{gathered} U=\frac{1}{2}CV^2 \\ \Rightarrow U=\frac{1}{2}\times(20\times10^{-6})\times9^2 \\ \Rightarrow U=8.1\times10^{-4}J \end{gathered}[/tex]The answer is
[tex]8.1\times10^{-4}J[/tex]