Consider a 342 μF capacitor charged to 1250 V in a defibrillator.

When charged to 1250 V, how much energy is stored in the capacitor? 9.60×10² J (in J)

Dear Student.
According to the question

A capacitor is a device that stores energy in the electric field between a pair of conductors on which equal but opposite electric charges have been placed.
The energy stored in a capacitor=1/2 CV²
Given,C=342μF=342×10^-6F ,V=31250V
∴E=1/2×342×10^-6×(1250)²= 2.67 * 10²J