Copy of 6_Current_Voltage_Resistance

Physics Agenda Overview

• Date: 11/14/2024

• Learning Objectives:

  • Understanding the analogy between electricity and water flow.

  • Defining electric current.

  • Learning about voltage as potential difference.

  • Exploring how potential difference is created.

  • Understanding electrical resistance and its dependencies.

  • Calculating electric field and electric potential.

  • Describing the relationship between charge and energy.

Flow of Water and Charge

• Sustained flow of charge requires a device to maintain potential difference.

  • Example: A battery functions like a pump in water flow by maintaining pressure differences.

Electric Current

• Definition: The rate of electric charge flow measured in amperes (A).

  • 1 Amp = 1 Coulomb per second.

  • Drift speed of electrons is slow due to collisions with atomic nuclei in conductive materials.

Voltage Sources

• Electric potential difference originates from chemical processes:

  • In batteries, chemical reactions produce electric potential energy.

Electric Resistance

• Current is reliant on:

  • Voltage across components.

  • Electrical resistance (measured in ohms).

• Resistors:

  • Circuit components that control the flow of current.

Factors Affecting Resistance

• Depend on:

  • Area: Inversely related to cross-sectional area (thinner = more resistance).

  • Length: Directly proportional (longer = more resistance).

  • Material: Different materials have different resistances (e.g., rubber vs. copper).

  • Temperature: Higher temperatures increase resistance.