Where Does the Extra Energy in a Capacitor Come From?

  • Context: Undergrad 
  • Thread starter Thread starter Ajay.makhecha
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    Capacitor Energy
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Discussion Overview

The discussion centers around the energy dynamics in a capacitor connected to a battery, specifically exploring the source of additional energy when the distance between the capacitor plates is increased. The scope includes conceptual understanding and reasoning about energy transfer and work done in electrical systems.

Discussion Character

  • Exploratory, Conceptual clarification

Main Points Raised

  • One participant notes that when the distance between capacitor plates is increased, the energy decreases by E, while the battery gains energy of 2E, prompting the question of the origin of the extra energy E.
  • Another participant asks for thoughts on where the extra energy might come from and suggests considering a quantity that equals the change in energy.
  • One participant proposes that the extra energy E is a result of work done by an external force.
  • A later reply agrees with the assertion that the extra energy comes from the work done by the external force.

Areas of Agreement / Disagreement

Participants appear to agree on the idea that the extra energy is related to work done by an external force, but the discussion does not resolve the broader question of the energy's origin.

Contextual Notes

The discussion does not clarify the specific assumptions regarding the system's mechanics or the definitions of energy involved, leaving some aspects unresolved.

Ajay.makhecha
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A capacitor is connected to a battery. If a person pulls the plate to increase the distance by 2d the decrease in energy between the plates is E. We observe energy gained by battery is 2E. From where does extra energy E come from.?
 
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Ajay.makhecha said:
From where does extra energy E come from.?
Where do you think it came from. Can you think of any quantity that is equal to the change in energy?
 
i think extra E came because of work done by external force
 

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