By the end of this unit a successful student should be able to:By the end of this unit successful students should be able to:
• Understand the concept of magnetic flux, so they can:
o Calculate the flux of a uniform magnetic field B through a loop of surface area A and arbitrary relative orientation (21-2)(APIIIE1a1)
• Describe qualitatively Faraday’s Law of induction – that an electric field is produced by a changing magnetic field : 21-1, 21-2, 21-3, 21-4, 22-1
• Describe Lenz’s Law – that a current produced by an induced emf moves in a direction so that its magnetic field opposes the original change in flux: 21-2, 21-3, 21-6
• Understand Faraday’s law and Lenz’s law, so they can:
o Recognize situations in which changing flux through a loop will cause an induced emf or current in the loop. (21-2, 21-5) (APIIIE1b1)
o Calculate the magnitude and direction of the induced emf and current in a loop of wire or a conducting bar under the following conditions:
The magnitude of a related quantity such as magnetic field or area of the loop is changing at a constant rate. (APIIIE1b2a)
• Apply Faraday’s law to simple AC transformers and describe conceptually the utility of using transformers and AC current. (See Tesla/Westinghouse vs. Edison) 21-7 (not usually on AP)
Target time (5% of test 6 class days)
3/28 Fri: Read: 21-1 à 21-8, 22-1
3/31 Mon: Read: Ch 31, Sections 1-3
Do: question 1a,b,c,d on p. 885
Do: pp. 886ff problems: 16, 26, 61
4/4 Fri Do Ch 21: 2, 6, 9, 11,12, 13, 15, 17, 18, 30
4/4 Fri: Test: Electromagnetic induction
Multiple Choice Question Survey:
Determine Magnetic Flux (21-2) 98:1
Use Faraday's Law to calculate Emf (21-2) 84:1 88:1, 93:1, 98: 1, 04:1
Use Faraday’s Law to determine if there is Emf (21-2) 84:1 88:1 98:1
Use Lenz’s Law to determine direction of induced current (21-2) 84:1, 88:1 98:1 04:2
Use Faraday’s & Ohm’s Laws to relate current to B algebraically 93:1
Prentice Hall's web page on Giancoli Chapter 21