Capacitor separated by a dielectric

AI Thread Summary
The discussion centers on calculating the maximum energy stored in a capacitor separated by a dielectric. The user questions why multiplying the maximum voltage (16,000 V) by the maximum charge (3.2 e-7 C) is incorrect for determining energy. It is clarified that the correct formula for energy is U = 1/2 * C * V^2, as drawing charge from the capacitor would decrease the voltage, making the initial assumption invalid. The key takeaway is that the energy calculation must consider the relationship between charge and voltage as the capacitor discharges. Understanding this relationship is essential for accurate energy calculations in capacitors.
EngineerHead
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Homework Statement



REFER TO ATTACHED SCREEN SHOT

Homework Equations


The Attempt at a Solution



My discrepancy is with the last question labeled "Exercise" (What is the maximum energy that can be stored in the capacitor?).

Since the max voltage is 16000V = 16000 J/C, why is multiplying the max voltage by the max charge (3.2 e-7 C) incorrect?
 

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The energy contained is U = 1/2*C*V^2
 
EngineerHead said:
why is multiplying the max voltage by the max charge (3.2 e-7 C) incorrect?
Because were you to start drawing off charge, the capacitor voltage would drop, so you don't have available that amount of charge at the max charged voltage.
 

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