1 / 28

Agenda

Agenda. Today Continuous Charge Distribution Tuesday – lab 5 & Quiz Wed&Fri – Chapter 24 Today Continuous Charge Distribution Gravity Equivalent Complex Layers HMWK CH. 22 Up Today HMWK Due Thurs. Fields & Potential In a Solid Gravity First. Earth M=M E R=R E V=(4/3) p R E 3

fayef
Download Presentation

Agenda

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. Agenda • Today Continuous Charge Distribution • Tuesday – lab 5 & Quiz • Wed&Fri – Chapter 24 • Today • Continuous Charge Distribution • Gravity Equivalent • Complex Layers • HMWK CH. 22 Up Today • HMWK Due Thurs.

  2. Fields & Potential In a SolidGravity First Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution? Solid Objects Density Volume Surface Area Mass Electrical Objects Charge & Charge Density

  3. Find the ZeroesUse reference 0 at infinity (Usual) Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution Where is FG=0? Where is PEG = 0?

  4. Gauss’s LawField then Force? Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution • Flux = Field x Area • = EA

  5. Gauss’s LawField at a point r? Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution Choose Surface so E Perp to it. Also, E constant across surface For point charge/sphere  Sphere

  6. Gauss’s LawField at a point r? Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution What if “Surface” inside Earth? What is m in equation?

  7. Gauss’s LawField at a point r? Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution What if “Surface” inside Earth? What is m in equation?

  8. Gauss’s LawField at a point r? Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution Vencl=(4/3)pr3

  9. Gauss’s LawField at a point r? Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution

  10. Where (r) is field zero? Earth M=ME R=RE V=(4/3)pRE3 SA=4pRE2 r=M/V=3ME/(4prE3) Even Distribution

  11. Where (r) is field zero? Inside: E=Gr(ME/rE3) Outside: E=GME/r2 Two Situations Where is “Special Point” Where r = rE Both must have same value Works: Both E=GME/rE2 Inside zero: at center of earth Gravitational pull cancels out Outside only zero at infinity Case similar for small - q & big + q What can be different for Elect? Material Dependence!

  12. Interesting Graph3D Charge Distribution Discontinuity Value Same Linear Inside 1/r2 outside E r r=rE r

  13. What if charged conductor? Metal Charge = +Q + + + + + + + Where is field zero? Everywhere inside metal Outside, E=kQ/r2 + + + + + + + + + + + + + + + + + + Outside is just air

  14. Interesting Graph3D Metal Discontinuity Value Not Same? 1/r2 outside E Zero Inside r r=rE r

  15. Real Graph3D Metal Discontinuity Value Same Exponential Decay Near Surface NanoScale 1/r2 outside E Zero Inside r r=rE r

  16. Potential of Charged Conductor? Metal Charge = +Q R=rE, etc.. + + + + + + + What is potential in a metal? Constant Where can we find a value? At edge, r=rE V=kQ/r outside V=kQ/rE at edge V=kQ/rE throughout + + + + + + + + + + + + + + + + + + Outside is just air

  17. Interesting Graph3D Metal Discontinuity Value Same 1/r outside V Constant Inside r r=rE r

  18. What if charged Insulator? • Insulator • Charge = +Q • =1 R=RE, etc… + + + + + + + Where is field zero? At center & Infinity Outside, E=kQ/r2 Inside, E=(k/k)(Qr/rE3) See k can make life interesting For now, k = 1. E=(k)(Qr/rE3) + + + + + + + + + + + + + + + + + + Outside is just air [k = 1]

  19. Interesting Graph3D Insulating Charge Discontinuity Value Same Linear Inside 1/r2 outside E r r=rE r What if k >1?

  20. Interesting Graph3D Insulating Charge Discontinuity Value Not Same? Linear Inside 1/r2 outside E r r=rE r What if k >1? Field becomes smaller inside

  21. Interesting Graph3D Insulating Charge Discontinuity Value Always Same! Exponential Bridge Linear Inside 1/r2 outside E r r=rE r What if k >1? Field becomes smaller inside In transition region from inside to outside, k changes value.

  22. What if charged Insulator?Potential, k = 1 • Insulator • Charge = +Q • =1 R=RE, etc… + + + + + + + + + + + + + + + + + + + + + + + + + Outside is just air [k = 1]

  23. Potential Graph3D Insulating Charge Discontinuity Value Always Same! Quadratic 1/r outside V r r=rE r What if k >1?

  24. What now? Metal Shell Outside is just air [k = 1] • Insulator • Charge = +Q • =1 R=RE, etc… + + + + + + + + + + + + + + + + + + + + + + + + +

  25. What now? Metal Shell Outside is just air [k = 1] What does charge On shell look like? • Insulator • Charge = +Q • =1 R=RE, etc… + + + + + + + + + + + + + + + + + + + + + + + + +

  26. What now? Metal Shell + Outside is just air [k = 1] + - What does charge On shell look like? - + • Insulator • Charge = +Q • =1 R=RE, etc… + - + + + + + + + + + + + + - + - + + + + + + + + + + + + - + - + + - - + -

  27. Metal Shell How much –q on shell? |+q|=|-q|=Q + + - - + • Insulator • Charge = +Q • =1 R=RE, etc… + - + + + + + + + + + + + + - + - + + + + + + + + + + + E = 0 in shell E=Qencl/A E=0  Qencl=0 + - + - + + - - + -

  28. Agenda • Today Continuous Charge Distribution • Tuesday – lab 5 & Quiz • Wed&Fri – Chapter 24 • Today • Continuous Charge Distribution (if Time) • Gravity Equivalent • Complex Layers • HMWK CH. 22 Up Today • HMWK Due Thurs.

More Related