chapter29 - 2 noitcaretni citengamortcele elgnis a fo...

Info icon This preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Electromagnetic induction r r kQ E ˆ 2 = v 2 0 ˆ 4 r r v q B × = v v π µ So far we have found that Electric charges create E-fields Moving electric charges create B-fields But this is not the whole story! 2 Electromagnetic induction Electric Fields can also be created by a changing Magnetic Field. Magnetic Fields can also be created by a changing Electric Field. This is described by “Faraday’s Law”. This will help complete the set of equations called Maxwell’s equations of electricity and magnetism. Electricity and Magnetism can be unified in a single theory! The electricity and magnetic forces are manifestations of a single “electromagnetic interaction”
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Electromagnetic induction Magnetic Flux
Image of page 2
Magnetic Flux The flux through an element of area is: To calculate the flux through the surface, we need to integrate: For the simple case of a flat surface, we obtain: B φ Magnetic flux
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
7 Clicker Question At what angle of orientation of the surface is the flux through the surface half of the maximum possible flux? A) φ = 0 degrees B) φ = 30 degrees C) φ = 45 degrees D) φ = 60 degrees E) None of the above B φ Faraday’s Law of Induction 8 dt d B Φ = ε Two new quantities introduced. 1. Magnetic Flux = Φ B 2. Electro Motive Force (EMF) = ε A changing (time-dependent) magnetic field “induces” (generates) an EMF ε . The magnitude of the EMF equals minus the rate of change of the flux.
Image of page 4
Important observations: Recall: EMF is not a force, but a source of voltage capable of generating power. The EMF is called “motional” EMF, to distinguish from “chemical” EMF (batteries) Recall: The magnetic flux through a closed surface is zero! (Gauss’ Law for B-fields) The surface for Faraday’s Law is an open surface! 10 Clicker Question We have a square imaginary loop with side of length a. There is a Magnetic Field that is uniform throughout the region as shown. How does the Magnetic Flux magnitude | Φ B | change if we halve the Magnetic Field strength and double the sides of the square loop? A) Flux goes to ½ original value B) Flux goes to ¼ original value C) Flux goes to 2 times original value D) Flux does not change E) None of the above X B
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Changing the magnetic flux 11 1. Change the strength of the Magnetic Field 2. Change the area of the loop 3. Change the orientation of the loop (A vector) and the B-field 12 A loop of wire is moving rapidly through a uniform magnetic field as shown. Is a non-zero EMF induced in the loop? A) No, there in no EMF B) Yes, there is an EMF Clicker Question
Image of page 6
A loop of wire is spinning rapidly about a stationary axis in uniform magnetic field as shown. True or False: There is a non-zero EMF induced in the loop. A) False, zero EMF
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern