# HP Cycle 43

## 6/2 - 6/7

Th 6/2

F 6/3

M 6/6

T 6/7

### π’β 6: Th 6/2, π΅β 8: Th 6/2 - β Faraday's Law

QUIZ on all of magnetism (does not include induction) Today.

After the quiz, we'll introduce the quantitative formula for flux in a uniform magnetic field: Ξ¦B = BAcosΞΈ. We'll see how we can quantify the current created by a changing magnetic flux in a loop by looking at Faraday's Law: Ξ΅ = -N ΞΞ¦B/Ξt where I = Ξ΅/R (Ohm's Law).

First watch the "Faraday's Law" video.

Then, we'll practice induction problems by doing β Positive Physics unit 27: electromagnetism "work" problems from the sections:

• magnetic flux

• electromagnetic induction 2

Homework: Electromagnetism Assessment on Wednesday, June 8th (does not include transformers, generators, or motors). Finish these β Positive Physics problems by Monday at 10pm. Only completion score counts. No late work will be accepted.

Optional Extra Practice: textbook chapter 20 exercises #4, 6, 9, 10

### π© 6: M 6/6, π¦ 8: F 6/3 - β motional emf

Today, we'll take a look at a moving bar in a magnetic field which will produce a motional emf. Using what we learned last time about Faraday's Law, we'll derive an equation that can help you understand this relationship. (Faraday's Law, Ξ΅ = -N ΞΞ¦/Ξt and I = Ξ΅/R (Ohm's Law)). Watch the video.

Then, we'll practice motional emf problems by doing β Positive Physics unit 27: electromagnetism "work" problems from the sections:

• electromagnetic induction 1

Homework: Electromagnetism Assessment on Wednesday, June 8th (does not include transformers, generators, or motors). Finish these β Positive Physics problems by Tuesday at 10pm. Only completion score counts. No late work will be accepted.

Optional Extra Practice: Read any sections in chapter 20 that seem unclear. Do textbook chapter 20 Example 20.4 (pages 704-705) and Exercises (page 725) #12-13 and check answers in the back of the book. Write down any questions you might have and bring them up at the beginning of next class. Then do at least #11-12 of page 2 of FYP: Electromagnetism (ANSWERS). The video will help you with these two problems.

### π 6: T 6/7, π 8: M 6/6 - β transformers

Today, we'll see how transformers work and how they can be useful. We'll use Faraday's Law of Induction to derive the relationships between primary/secondary numbers of coils, voltage, and current in ideal transformers. (Know the ideal transformer equation.)

Watch this video on how transformers work:

You can check out this demo to see a transformer in action:

Then, we'll practice ideal transformer problems by doing β Positive Physics unit 27: electromagnetism "work" problems from the section:

• transformers

Presentation: Electromagnetic Induction Presentation continued

Homework: Electromagnetism Assessment next class - Wednesday, June 8th (does not include transformers, generators, or motors). Finish these β Positive Physics problems by Wednesday at 10pm. Only completion score counts. No late work will be accepted. Then, review concepts from last unit on circuits to answer questions about Power Lost in the Transport of Power. Imagine the circuit in the questions is an AC circuit with two resistors as shown:

Optional Extra Practice: Another transformer video. Do page 2 of FYP: Electromagnetism (ANSWERS).