Question

To what potential should you charge a 0.900 μf capacitor to store 1.50 j of energy

Answer 1

The energy stored in a capacitor is given by
$U= \frac{1}{2} CV^2$
where C is the capacitance and V the voltage applied.
In our problem, $C=0.900 \mu F=0.9 \cdot 10^{-6} F$, while the energy is $U=1.5 j$. We can then solve the formula to find V:
$V= \sqrt{ \frac{2U}{C} }= \sqrt{ \frac{2\cdot 1.5 J}{0.9\cdot 10^{-6} F} }=1826 V$