Lecture Notes: Electric Potential Energy vs. Electric Potential

Introduction

• Clarification on terminology: difference between "electric potential energy" and "electric potential."
• Importance of understanding these terms before learning about voltage.

Definitions

• Electric Potential Energy
  • Associated with a charge/particle.
  • Only a particle with charge can have energy.
• Electric Potential
  • Associated with a position in space.
  • Helps determine potential energy by multiplying with charge.

Example Scenario: Uniform Electric Field

• Setup:
  • Infinite uniformly charged plate with a constant electric field.
  • Positive 2-coulomb charge starts 3 meters away, moved to 1 meter.
• Calculating Electric Potential Energy Difference:
  • Work needed to move charge: Apply force opposite to electrostatic force.
  • Electric field given as 3 newtons per coulomb.
  • Force on particle: Electric field \times Charge = 6 newtons.
  • Total work: Force \times Distance = 12 joules.
  • Higher potential energy at a closer position to the repelling charge.

Electric Potential (Voltage)

• Definition:
  • Work required per unit charge to move charge between points.
  • Example: 12 joules for 2 coulombs = 6 joules per coulomb.
  • Equivalent to the term voltage, measured in volts.
• Key Distinction:
  • Electric potential energy is particle-specific.
  • Electric potential is independent of charge size and depends on position.
• Analogy to Gravitation:
  • Similar to gravitational potential energy divided by mass.

Importance of Voltage

• Provides information about potential energy difference without needing charge size.
• Useful for comparing points in space rather than charges at points.

Conclusion

• Future topic: calculating electric potential difference between points.
• Clarification aims to prevent confusion in terms understanding.

Next Steps

• Upcoming problems and examples in the next video to deepen understanding.