Electromagnetic Induction
Core Sentence / 核心句
Electromagnetic induction is the production of EMF by changing magnetic flux.
中文理解：只要 circuit 所关联的 magnetic flux 随时间变化，就会出现 induced EMF；若 circuit closed，还会出现 induced current。
Core Law / 核心定律
How Flux Can Change / 磁通如何变化
- magnetic field magnitude changes；
- loop area changes；
- loop orientation changes；
- conductor enters or leaves a field；
- field distribution changes；
- conductor moves through a field。
Two Views / 两种视角
- microscopic: Lorentz Force separates charges in a moving conductor；
- macroscopic: Faraday’s Law relates circuit EMF to flux change。
Energy / 能量
induced current 的 magnetic effect opposes the change producing it。mechanical or field-source work supplies the electrical energy。
Watch Out / 易错点
- electrostatic Induction 与 electromagnetic induction 是不同概念。
- motion is sufficient in many cases, not necessary。
- flux change, not field alone, controls induction。
- direction follows Lenz’s law。
Search and Source Mentions / 搜索与出现位置
Mentioned In / 出现位置
- 第13次正课 · source mechanism
- 第13次正课 · Faraday law
- 第13次正课 · induction mechanisms
- 第14次正课 · direction
- 第14次正课 · self-induction