What is the capacitance of this device?

sci0x
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An automatic external defibrillator (AED) delivers 125J of energy at a voltage of 1050V. What is the capacitance of this device?

Possible Ans
Capacitance is charge / voltage.
We have the voltage so how can you get a value for charge?
 
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Do you know the formula for energy stored in a capacitor?
 
oh ok,
so U = 0.5qV
so q = 0.238 V

Fill into capacitance formula and i got 2.267 x 10^-4 C/V
Thanks
 
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