Electric Potential and Potential Difference
Electric Potential
- Electric potential is the amount of electrical potential energy associated with charges, particularly electrons.
- Potential energy is stored when charges (electrons) are forced together, and released when they are allowed to move freely.
- Electric potential can be described as the amount of energy needed to move a quantity of electrons close to each other.
Units and Definitions
- Energy is measured in joules (J).
- The quantity of electrons is measured in coulombs (C).
- Electric potential is commonly known as voltage (V), which is the amount of energy per amount of electrons, or joules per coulomb (J/C).
- Voltage = \frac{Energy}{Charge}
- V = \frac{J}{C}
Understanding Coulombs
- A coulomb represents a specific quantity of electrons.
- Historically, the concept of positive and negative charges was recognized before the discovery of electrons.
- The electron was discovered in 1898.
- One coulomb is defined as approximately 6.2 \times 10^{18} electrons.
The Electron Charge
- Robert Millikan determined the charge of a single electron.
- One electron has a charge of approximately 1.6 \times 10^{-19} coulombs.
- The number of electrons in one coulomb is derived from dividing one coulomb by the charge of a single electron.
- A coulomb is essentially a "chunk" of electrons.
Electric Potential vs. Electric Potential Energy
- Electric potential (voltage) and electric potential energy are related but not the same.
- Electric potential is the energy per unit charge (joules per coulomb).
- The amount of energy in electrons, how closely together they are is the amount of energy associated with it.
Review and Preview
- The concepts covered serve as a review of fundamental principles.
- Upcoming topics include Kirchhoff's laws and the behavior of voltage and current in series and parallel circuits.
- Suggested reading: Textbook sections 11.1, 11.3, and 11.5.