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Conservation of Electric Energy

Chloe Sanchez

Chloe Sanchez

7 min read

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Study Guide Overview

This study guide covers conservation of electric energy in closed systems and its applications in circuits. It explains the relationship between electric fields and work, including the formula W = qΔV and its sign conventions. It also discusses electric potential energy (U), its relationship to electric potential (V), and how it relates to Coulomb's Law and electric field strength. Finally, the guide provides exam tips, practice questions on these concepts, and a scoring rubric.

#AP Physics 2: Electric Energy & Potential - The Night Before

Hey there, future physicist! Let's get you prepped for the AP Physics 2 exam with a high-impact review of electric energy and potential. This guide is designed to be your best friend tonight, focusing on clarity, quick recall, and those crucial exam connections.

#Conservation of Electric Energy

Key Concept

The total electric energy in a closed system remains constant. Energy transforms, but it doesn't disappear! 💡

  • Fundamental Principle: A direct consequence of the law of conservation of energy.
  • In Circuits: Energy supplied = Energy used + Energy stored. Think of it like a bank account; what goes in must come out (or stay in).
  • Applications: Understanding circuits, batteries, generators, and transformers. It's the backbone of electrical analysis!

#Electric Fields & Work

Key Concept

Work done by an electric field equals the change in electric potential energy of a charge. ⚡

  • Definition: Work is done by the field when moving a charge from one point to another.
  • Formula: W=qΔVW = q\Delta VW=qΔV, where:
    • WWW = Work (Joules)
    • qqq = Charge (Coulombs)
    • ΔV\Delta VΔV = Change in electric potential (Volts)
  • Sign Convention:
    • Positive work: Final potential > Initial potential.
    • Negative work: Final potential < Initial potential.
  • Importance: Analyzing circuits and devices, calculating energy stored in capacitors.
Memory Aid

Think of it like a ball rolling down a hill: The electric field does work, converting potential energy to kinetic energy (or vice versa). Positive work means the charge is moving 'downhill' in terms of electric potential, and negative work means it's moving 'uphill'.

#Work and Coulomb's Law

  • **Bringing like charges together or separating opposite ch...
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Question 1 of 11

A light bulb is connected to a battery. What happens to the electrical energy supplied by the battery? 🤔

It disappears completely

It is transformed into light and heat energy

It is stored in the wires

It is converted to potential energy