A parallel plate capacitor stores charge, and thus, stores energy in the form – [Free] B38
A parallel plate capacitor stores charge, and thus, stores energy in the form of electric potential energy. The total energy stored in a parallel plate capacitor does NOT depend on
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Energy Stored in a Parallel Plate Capacitor
1. A parallel plate capacitor stores charge and thus stores energy in the form of electric potential energy. The total energy stored in a parallel plate capacitor does NOT depend on __________.
The energy stored in a capacitor is given by any of the following equivalent expressions:
U = (1/2) C V²
U = Q² / (2C)
U = Q² / (2C)
Where:
- U is the energy stored
- C is the capacitance
- V is the voltage across the plates
- Q is the magnitude of the charge stored
Important Observation:
Both formulas involve squares of either voltage (V²) or charge (Q²). This implies that:
- Only the magnitude of voltage or charge matters
- The sign or polarity of the voltage or charge has no effect on energy stored
Example: Suppose you reverse the applied voltage, turning +V into -V. The energy becomes:
U = (1/2) C (–V)² = (1/2) C V²
Clearly, the energy remains unchanged.
Similarly, if the charge is reversed (–Q instead of +Q), the energy becomes:
U = (–Q)² / (2C) = Q² / (2C)
Again, the result remains unchanged.
✅ Final Answer: The total energy stored in a parallel plate capacitor does NOT depend on the sign (polarity) of the charge or voltage.