Battery

Definition

A battery is a device that converts chemical energy into electrical energy to provide a steady flow of direct current (DC). It consists of one or more electrochemical cells with external connections for powering electrical devices.

5 Must Know Facts For Your Next Test

1. The electromotive force (emf) of a battery is the potential difference between its terminals when no current is flowing.
2. Internal resistance within the battery affects the terminal voltage and reduces the effective power output.
3. The terminal voltage can be calculated using $V = \text{emf} - Ir$, where $I$ is the current and $r$ is the internal resistance.
4. In series circuits, batteries add their voltages together, while in parallel circuits, they increase total capacity without increasing voltage.
5. The efficiency of a battery decreases over time due to chemical degradation and increased internal resistance.

Review Questions

• What happens to the terminal voltage when current flows through a battery with internal resistance?
• How does connecting batteries in series differ from connecting them in parallel regarding voltage and capacity?
• Explain how internal resistance affects the performance of a battery over time.

Related terms

Electromotive Force (emf): The maximum potential difference between two terminals of a battery when no current flows.

Internal Resistance: The inherent resistance within the battery that causes energy loss as heat and reduces terminal voltage.

Direct Current (DC): An electric current flowing in one direction only, typically supplied by batteries.