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Regarding gradient vector

  1. Nov 14, 2011 #1
    As we know grad F (F surface) is in normal direction. But we also have (grad F(r)) x r = F'(r) (r) x r = 0
    this implies grad F is in direction of r i.e., radial direction. Radial and normal directions need not be same. Can any öne clarify THE DIRECTION OF GRAD VECTOR?
     
    Last edited: Nov 14, 2011
  2. jcsd
  3. Nov 15, 2011 #2
    Gentle reminder
     
  4. Nov 15, 2011 #3

    HallsofIvy

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    In your second formula, you refer to "F(r)" so you are assuming that F depends only on r and so is spherically symmetric. The first formula does not assume that .
     
  5. Nov 16, 2011 #4
    Got it! Thanks!
     
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