The potential energy stored in a capacitor is given by:
[tex]U= \frac{1}{2}CV^2 [/tex]
where
C is the capacitance of the capacitor
V is the potential difference across the plates of the capacitor
In our problem,
[tex]C=150 \mu F= 150 \cdot 10^{-6} F[/tex]
[tex]V=5 V[/tex]
Therefore, the potential energy of the capacitor is
[tex]U= \frac{1}{2}(150 \cdot 10^{-6}F)(5 V)^2 = 1.88 \cdot 10^{-3}J [/tex]
