Energy Stored by Capacitor Video Lessons

Concept

# Problem: In open-heart surgery, a small amount of energy will defibrillate the heart. (a) What voltage is applied to the 8.28 μF capacitor of a heart defibrillator that stores 42.3 J of energy? _________ kV(b) Find the amount of stored charge._________ mC

###### FREE Expert Solution

Energy stored in a capacitor:

$\overline{){\mathbf{U}}{\mathbf{=}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbit{C}}{{\mathbit{V}}}^{{\mathbf{2}}}}$

The charge stored in a capacitor:

$\overline{){\mathbf{Q}}{\mathbf{=}}{\mathbit{C}}{\mathbit{V}}}$

(a)

C = 8.28 μF(10-6F/1μF) = 8.28 × 10-6 F

U = 42.3 J

Using the expression for energy:

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###### Problem Details
In open-heart surgery, a small amount of energy will defibrillate the heart.

(a) What voltage is applied to the 8.28 μF capacitor of a heart defibrillator that stores 42.3 J of energy?
_________ kV
(b) Find the amount of stored charge.

_________ mC