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ganeshie8

in 3D, why theta = l/r^2. in 2D theta = l/r. im not good with non-euclidean geometries.. can somebody pls show a proof or give a good link pls

  • one year ago
  • one year ago

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  1. mukushla
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    *

    • one year ago
  2. experimentX
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    due to the nature of conservation of flux

    • one year ago
  3. ganeshie8
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    its related to 1/r^2 relationship ?

    • one year ago
  4. experimentX
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    yep

    • one year ago
  5. ganeshie8
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    yeah i believe everything that propagates in 3D follows that

    • one year ago
  6. experimentX
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    if universe were flat ... the law of gravity would be F = Gm1m2/r instead of r^2 <--- at least that's how i'm thinking these days

    • one year ago
  7. ganeshie8
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    yes i get that.. im looking for a proof. i got stuck while refreshing electrostatics when i come across flux around point charge

    • one year ago
  8. experimentX
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    i think Gauss law is fine ...

    • one year ago
  9. ganeshie8
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    gauss law is next topic .... ill see if it gets addressed .. thank you :)

    • one year ago
  10. ganeshie8
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    there maynot be any derivation. its just a fact this 1/r^2 relation for 3D model

    • one year ago
  11. experimentX
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    this is very easy to visualize ... in terms of light. the intensity of light decreases by /r^2 ... because light diverges in all 3d directions. |dw:1344027074813:dw|

    • one year ago
  12. experimentX
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    |dw:1344027132708:dw| the total light must be same in both surface.

    • one year ago
  13. experimentX
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    let's say ... this is due to the geometry of the sphere (surface) in 3D ... and the conservation of theorem.

    • one year ago
  14. experimentX
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    *conservation law

    • one year ago
  15. ganeshie8
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    i see that... total light has to escape throuh both the spherical surfaces. its same light that goes out

    • one year ago
  16. experimentX
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    yep ... or i must be stupid.

    • one year ago
  17. ganeshie8
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    this is a law is it.. we cannot derive 1/r^2 relationship... like we derive 1/r in circle for theta

    • one year ago
  18. ganeshie8
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    lol

    • one year ago
  19. ganeshie8
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    everything seems new.. now when i open my books again

    • one year ago
  20. experimentX
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    what do you mean by 1/r in circle ... can you elaborate a bit?

    • one year ago
  21. experimentX
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    my suggestion ... never open a book :D

    • one year ago
  22. ganeshie8
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    il get back... read some more. actually im looking for some derivation of relation between angle and area for a sphere

    • one year ago
  23. experimentX
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    you need solid angle

    • one year ago
  24. ganeshie8
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    yeah looks like we need to consider surface area of sphere... i think im getting it now.. il try... thank you :D

    • one year ago
  25. experimentX
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    yw!!

    • one year ago
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