📚 Theory

The electric potential energy stored in a capacitor is equal to the work done by an external force to separate that amount of charge on the capacitor.

Key Concepts:

  • Capacitors store electrical energy in the form of separated charges
  • The energy stored depends on the charge, voltage, and capacitance
  • When a capacitor discharges, the stored energy is converted to other forms
  • The energy can be calculated using any of the three equivalent formulas

Electric Potential Energy Equations

$$U_c = \frac{1}{2} Q \Delta V = \frac{1}{2} CV^2 = \frac{Q^2}{2C}$$

Where: $U_c$ = electric potential energy, $Q$ = charge, $V$ = voltage, $C$ = capacitance

These three forms are mathematically equivalent and can be used interchangeably depending on which variables are known.

🎛️ Capacitor Energy Simulator

How it works: Adjust the capacitance and voltage to charge the capacitor, then press "Discharge Capacitor" to see the stored electrical energy convert to kinetic energy and move the train around the circular track!

Note: This simulation takes some mechanical liberties for visualization purposes.

5.0 μF
12 V

📝 Exercises

Calculate Capacitor Energy

Calculate the electric potential energy stored in a capacitor.

μJ

Round your answer to the nearest hundredth.