Lecture Notes: Understanding Batteries and Potential Difference

Introduction

• Objective: Learn to describe a battery and calculate the potential difference produced by it.
• Context: Builds on previous lessons about current and potential difference in series and parallel circuits.

What is a Battery?

• Definition: A battery is two or more cells connected together.
• Symbol: Shown in diagrams as two cells in line.
• Key Point: Cells in a battery must be connected in the same direction (positive ends aligned).

Calculating Potential Difference in Batteries

Example 1: Two Cells in Series

• Single Cell Potential Difference: 9 volts.
• Battery Formation: Two cells in series.
• Total Potential Difference Calculation:
  • Formula: Total = Number of Cells * Voltage per Cell
  • Calculation: 2 * 9V = 18V.

Example 2: Three Cells in Series

• Given: Each cell has a 9V potential difference.
• Calculation: 3 * 9V = 27V total.*

Example 3: Zero Potential Difference

• Scenario: Two cells, one in correct direction and one in opposite.
• Result: Potential differences cancel, resulting in 0V total.

Final Example: Mixed Directions

• Scenario: Three cells, two in correct direction, one in opposite.
• Calculation:
  • Correctly Aligned Cells: 2 * 9V = 18V.
  • Incorrect Cell cancels one correct cell.
  • Total: 18V - 9V = 9V.*

Conclusion

• Skills Learned: Describing a battery and calculating its potential difference.
• Further Practice: Exercises available in the vision workbook for additional problems on potential difference calculations.