A heart defibrillator delivering 400 J of energy by discharging a capacitor initially at 10,000 V has a capacitance of 8.00 µF (see Example 18.11 of the textbook). The energy stored in the capacitor of a second defibrillator is only 304 J but the charge in both defibrillators is the same. What is the voltage of the second defibrillator?