#AP Physics C: E&M - Unit 5: Electromagnetic Induction & Maxwell's Equations ⚡

#Overview 🧭

Hey there, future physicist! You've reached the final stretch of AP® Physics C: E&M! This unit is all about how electricity and magnetism intertwine, focusing on creating magnets with electricity, and exploring applications like motors, rail guns, and transformers. We'll also touch on Maxwell's Equations, the very foundation of all E&M concepts. This unit makes up a significant portion of the exam (14-20%), so let's make sure you're ready to ace it! 🚀

This unit accounts for 14-20% of the AP exam, making it a high-value topic. Make sure to review all the concepts thoroughly.

#5.1: Electromagnetic Induction

#Making Magnets from Electricity 🧙

Electromagnetic Induction is the process of generating a voltage using magnetic fields. If this voltage is in a complete circuit, it creates a current. Remember, in Unit 4, we saw how a current creates a magnetic field? Well, here we're doing the reverse! 🔄

Take a moment to explore this PhET simulation, especially the Pickup Coil tab. Notice what makes the bulb light up?

*Image created by the author using PhET*

The key is that the magnet must be moving! Just like a moving charge creates a magnetic field, a moving magnetic field induces a potential difference. 💡

#Magnetic Flux 🌐

Remember electric flux from Unit 2? Now, we're diving into magnetic flux to understand Faraday's Law. It’s calculated using a similar formula:

$$Φ_B = ∫ overrightarrow{B} ⋅ doverrightarrow{A}$$

*Image from electricalacademia.com*

Where:

• B is the magnetic field strength.
• dA is a tiny area chunk.
• θ is the angle between the magnetic field and area vectors.

The unit of magnetic flux is Tm², also known as a Weber (Wb). 📏

Magnetic flux can change in three ways:

*Image from physics.stackexchange.com*

• Changing the magnetic field strength (B).
• Changing the area (A) of the loop in the field.
• Changing the angle (θ) between the field and area.

#Faraday's Law & Lenz's Law 🔦

Faraday's Law tells us...