1 / 11

Physics 2112 Unit 12

Physics 2112 Unit 12. Today’s Concept: Magnetic Force on Moving Charges. Magnetic Force. Electric Field Any particle can cause E field Any particle affected by E field. Magnetic Field Only moving particle can cause B field Only moving particle affected by B field. Unit 12, Slide 2.

delores
Download Presentation

Physics 2112 Unit 12

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. Physics 2112Unit 12 Today’s Concept: Magnetic Force on Moving Charges

  2. Magnetic Force • Electric Field • Any particle can cause E field • Any particle affected by E field • Magnetic Field • Only moving particle can cause B field • Only moving particle affected by B field Unit 12, Slide 2

  3. Units Units: Telsa(N/(Cm/sec)) Extremely large field so sometimes use Gauss = (10-4T) • Earth ~ 0.6 Gauss • Frig Magnet ~ 0.01T (100 Gauss) • MRI 1.5 ->5.0 Tesla (15,000 – 30,000 Gauss) • LHC 8.4 Tesla • World’s Record 45 Tesla (National High Magnetic Field Laboratory at Florida State) Unit 12, Slide 3

  4. Cross Product Review • Cross Product different from Dot Product is a scalar; is a vector proportional to the component of Bparallel to A proportional to the component of Bperpendicular to A • Definition of • Magnitude: |A||B|sinq Direction: perpendicular to plane defined by AandBwith sense given by right-hand-rule Unit 12, Slide 4

  5. Remembering Directions: The Right Hand Rule y x F B qv z Unit 12, Slide 5

  6. Example 12.1 (Acceleration of proton) The earth’s magnetic field is pointed roughly 70o from the horizontal in Chicago. What would the acceleration of a proton be if it were moving at 1% of the speed of light in the horizontal direction? Unit 12, Slide 6

  7. CheckPoint 2 Three points are arranged in a uniform magnetic field. The B field points into the screen. A positively charged particle is located at point A and is stationary. The direction of the magnetic force on the particle is: right left into the screen out of the screen zero Unit 12, Slide 7

  8. CheckPoint3 Three points are arranged in a uniform magnetic field. The B field points into the screen. Now the positive charge moves from point A toward B. The direction of the magnetic force on the particle is: right left into the screen out of the screen zero Unit 12, Slide 8

  9. Motion of Charge q in Uniform B Field v x xxxxxx x xxxxxx x xxxxxx x xxxxxx x xxxxxx x xxxxxx F F v v F F v • Force is perpendicular to v • Speed does not change • Uniform Circular Motion R • Solve for R: Uniform B into page q q q q Demo Unit 12, Slide 9

  10. Example 12.2 (Analysis Magnets) A proton enters the magnetic field of an analysis magnet at Fermilab and it deflected by an angle of Q = 10o. The field has a strength of 0.2T and a length of 2meters. What is the speed of the incoming proton? Q X XXXXXX X XXXXXX X XXXXXX X XXXXXX X XXXXXX X XXXXXX X XXXXXX Q R sinQ Unit 12, Slide 10

  11. Follow up Photograph of track in bubble chamber (pre 1984) Electronic version of same thing (top quark event at CDF) The analysis magnet Question: In the previous example how did you know it was a proton? Unit 12, Slide 11

More Related