Parallel-Plate Vacuum Capacitor

  • Thread starter Thread starter LostinPhysics
  • Start date Start date
  • Tags Tags
    Capacitor Vacuum
Click For Summary
SUMMARY

The discussion focuses on the energy stored in a parallel-plate vacuum capacitor when the separation between the plates is altered. Initially, the capacitor has energy U stored with plate separation x1. When the separation is decreased to x2, the energy can be recalculated using the formula U = Q² / (2C), where Q remains constant since the capacitor is disconnected from the potential source. The capacitance for both configurations must be determined to find the new energy stored after the change in separation.

PREREQUISITES
  • Understanding of capacitor fundamentals, specifically parallel-plate capacitors.
  • Familiarity with the formulas for capacitance and energy storage in capacitors.
  • Knowledge of electric charge conservation principles.
  • Basic algebra skills for manipulating equations.
NEXT STEPS
  • Study the derivation of the capacitance formula for parallel-plate capacitors.
  • Learn how to calculate energy stored in capacitors using different configurations.
  • Explore the implications of charge conservation in disconnected capacitors.
  • Investigate the effects of varying plate separation on capacitance and energy storage.
USEFUL FOR

Electrical engineers, physics students, and anyone interested in understanding capacitor behavior in circuit design and energy storage applications.

LostinPhysics
Messages
3
Reaction score
0
If a parallel-plate vacuum capacitor, with its plates separated by a distance of x1 has an amount of energy equal to U stored in it. The separation is then decreased to x2 .

What is the energy now stored if the capacitor was disconnected from the potential source before the separation of the plates was changed? I know that I am suppose to use the formula C= Q/V but how do I put U in terms of x1 and x2?
 
Physics news on Phys.org
As the battery is disconnected, the charge on the capacitor plates becomes constant. Now by changing capacitance the potential difference will change and hence it is batter to use the formula Q^2 /2C of the energy.

Capacitance in the two situations are to be calculated and Q is calculated by first situation only.
 

Similar threads

Charge on a grounded conducting sphere in a uniform electric field, after ungrounding and movement
  • · Replies 1 ·
Replies
1
Views
2K
Comparing energy lost by the battery & energy gained by the capacitor.
  • · Replies 5 ·
Replies
5
Views
2K
Questions about a capacitor with 4 parallel plates
  • · Replies 14 ·
Replies
14
Views
1K
Two different dielectrics between parallel-plate capacitor
  • · Replies 6 ·
Replies
6
Views
2K
Why Capacitors in Parallels vs. Series: Coaxial Capacitor Case
  • · Replies 2 ·
Replies
2
Views
2K
A disconnected capacitor with two dielectrics in parallel
  • · Replies 8 ·
Replies
8
Views
2K
Capacitance and Dielectrics in Parallel Plate Capacitors
  • · Replies 2 ·
Replies
2
Views
2K
Parallel Plate Capacitor Filled with Many dielectrics
  • · Replies 20 ·
Replies
20
Views
4K
What happens to the capacitance after increasing distance?
  • · Replies 2 ·
Replies
2
Views
2K
Method of images between parallel plate capacitor
  • · Replies 20 ·
Replies
20
Views
3K