How Does a Capacitor's Energy Change Over Time?

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SUMMARY

The discussion centers on the behavior of a capacitor in a circuit over time. When the switch is ON for an extended period, the current in the circuit becomes zero as the capacitor reaches full charge. The energy stored in the capacitor can be calculated using the formula U = 1/2 CV^2. Once the capacitor is connected to a resistor, it discharges completely, resulting in zero energy stored, with the energy being converted into heat.

PREREQUISITES
  • Understanding of capacitor charging and discharging principles
  • Familiarity with the formula U = 1/2 CV^2
  • Basic knowledge of electrical circuits and components
  • Concept of energy conversion in resistive loads
NEXT STEPS
  • Study the behavior of capacitors in RC circuits
  • Learn about energy dissipation in resistors
  • Explore the impact of capacitance and voltage on energy storage
  • Investigate transient analysis in electrical circuits
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Students studying electrical engineering, educators teaching circuit theory, and anyone interested in understanding capacitor behavior in circuits.

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Homework Statement


q5.jpg

Questions 1-2:
Switch is ON and left for a very long time.
1) current in circuit after this time
2) energy in capacitor after this time

Questions 3-4:
Capacitor then hooked up to resistor.
3)Energy after another long time.
4)What happens to the energy that was in the capacitor before it was hooked up to the resistor.

Homework Equations


U = 1/2 CV^2

The Attempt at a Solution


1) current is 0 because after the capacitor is fully charged no current flows
2)just solve using U=1/2CV^2
3)Energy = 0 because capacitor would be discharged
4)energy goes into heat

I'm not sure about all these answers... can someone let me know if my thought process is correct? Thanks for any help!
 
Last edited:
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Looks okay to me.
 

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