Answer
$U_1=5.55\times10^{-3}J$
Work Step by Step
$U=\frac{1}{2}CV^2$
For compacitor 1, this is the same as:
$U_1=\frac{1}{2}C_1V_1^2$
We substitute the known values to obtain:
$U_1=\frac{1}{2}(10\times10^{-6}\times(33.3)^2)$
$U_1=5.55\times10^{-3}J$
