1 / 13

Winter wk 8 – Thus.24.Feb.05

Winter wk 8 – Thus.24.Feb.05. Review Ch.30 – Faraday and Lenz laws Ch.32: Maxwell Equations ! Gauss: q E Ampere: I B Faraday: dB/dt E (applications) Maxwell: dE/dt B Magnetism in matter. Energy Systems, EJZ. Gauss: charge q  E field. No magnetic charges.

zahur
Télécharger la présentation

Winter wk 8 – Thus.24.Feb.05

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Winter wk 8 – Thus.24.Feb.05 Review Ch.30 – Faraday and Lenz laws Ch.32: Maxwell Equations! • Gauss: q E • Ampere: I B • Faraday: dB/dt E (applications) • Maxwell: dE/dt B Magnetism in matter Energy Systems, EJZ

  2. Gauss: charge q  E field No magnetic charges Practice: P2 (p.883)

  3. Ampere: current I B field

  4. Faraday: dB/dt  E field

  5. Lenz’s law tells DIRECTION of e Induced emf opposes change in flux: Induced current Ii creates an induced field Bi to oppose any change in the external flux. In what direction does current flow, in each diagram?

  6. Practice with Lenz’s law In what direction does current flow, in each loop

  7. Generators & Transformers

  8. AC power depends on transformers Step-up transformer: higher voltage, lower current Step-down: lower voltage, higher current

  9. Induced magnetic fields: dE/dt  B Recall Faraday: changing magnetic flux  E field Symmetry: changing electric flux  B Practice: P 5, 10 (p.884)

  10. Ampere-Maxwell Law • What can cause a magnetic field B? • Ampere: Current IB: • Maxwell: changing EB:

  11. Practice with magnetic induction Q1 (p.882): Is E increasing or decreasing? Q2: Which loop has the greatest magnetic circulation?

  12. Maxwell Eqns  EM waves Next week we will combine the Maxwell equations to • Derive electromagnetic waves • Derive the speed of light

  13. Magnetism in matter Earth’s B field is due to currents in the molten outer core Electron spin ~ current loop  magnetic moment m=IA Magnetic materials have regions of aligned electron spin Probs. 67, 72, 73

More Related