1 / 19

6:00–7:00PM THU 11 MAR: Second Exam (Chapters 24.9-28.8 / HW04-06) Room Lockett 6

6:00–7:00PM THU 11 MAR: Second Exam (Chapters 24.9-28.8 / HW04-06) Room Lockett 6. Physics 2102 Jonathan Dowling. Lecture 13: THU 04 MAR 10. Aurora Borealis. Magnetic fields Ch.28.1–5. “I’ll be back…. How Do You Use Magnetic Fields in Your Everyday Life!?.

daphne-ayers
Download Presentation

6:00–7:00PM THU 11 MAR: Second Exam (Chapters 24.9-28.8 / HW04-06) Room Lockett 6

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. 6:00–7:00PM THU 11 MAR: Second Exam (Chapters 24.9-28.8 / HW04-06) Room Lockett 6

  2. Physics 2102 Jonathan Dowling Lecture 13: THU 04 MAR 10 Aurora Borealis Magnetic fields Ch.28.1–5 “I’ll be back….

  3. How Do You Use Magnetic Fields in Your Everyday Life!?

  4. Electric vs. Magnetic Fields • Electric fields are created: • microscopically, by electric charges (fields) of elementary particles (electrons, protons) • macroscopically,by adding the field of many elementary charges of the same sign • Magnetic fields are created : • microscopically, by magnetic “moments” of elementary particles (electrons, protons, neutrons) • macroscopically, by • adding many microscopic magnetic moments (magnetic materials); or by • electric charges that move (electric currents)

  5. Magnetic Field Direction E + – Compare to Electric Field Directions B FROM North Poles TO South Poles

  6. Ritchie’s Rule for Magnets Opposite Poles Attract Like Poles Repel

  7. Magnetic vs. Electric Forces We know that an electric fields exists because it accelerates electric charges, with a force independent of the velocity of the charge, proportional to the electric charge: FE = qE We know that a magnetic field exists because it accelerates electric charges in a direction perpendicular to the velocity of the charge, with a magnitude proportional to the velocity of the charge and to the magnitude of the charge: FB= q vxB Magnetic forces are perpendicular to both the velocity of charges and to the magnetic field (electric forces are parallel to the field). Since magnetic forces are perpendicular to the velocity, they do no work! (W=F· r) Speed of particles moving in a magnetic field remains constant in magnitude, ONLY the direction changes. Kinetic energy is constant! (no work).

  8. Magnetic vs. Electric Forces Electric Force on Charge Parallel to E: +q Magnetic Force on Charge Perpendicular to B and v. +q

  9. Definition of Magnetic Field Definition of Electric Field: Definition of Magnetic Field:

  10. Thompson Experiment & The Discovery of the Electron Forces Balance: v=E/B

  11. III: vB=E I: E=0, B=0 y II: E≠0, B=0 L

  12. The Hall Effect — Charge Flow in Conductors is From Electrons: Benjamin Franklin’s Biggest Blunder!

  13. Hall Voltage for Positive Charge Carriers The current expressed in terms of the drift velocity is: Fm = vdBsin90° At equilibrium: A = Wd Fe = qE = qV/W

More Related