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Homework Help: Ranking the E-field from a graph! alittle confused.

  1. Sep 28, 2005 #1
    Figure 24-27 gives the electric potential V as a function of x.
    Figure


    (a) Rank the five regions according to the magnitude of the x component of the electric field within them, greatest first (use only the symbols > or =, for example 2=4>1=3>5).

    I got the other 2 parts (b) and (c) right. What I thought was, the longer the space is in the x direction the bigger the magntude of the electric field. Which was wrong, i also tried to find the area under of the curve which was also wrong. When I tried to rank them from the area under the curve I got:
    3>4=2>1>5
    When i ranked them from the length fo the x distance, i got:
    4>1=3=5>2

    both wrong, what did i do wrong?
    :bugeye:
     
  2. jcsd
  3. Sep 28, 2005 #2

    Tom Mattson

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    [tex]E=-\frac{dV(x)}{dx}[/tex]

    That means that the greater the slope of [itex]V(x)[/itex], the greater the absolute value of [itex]E[/itex].
     
  4. Sep 28, 2005 #3
    Awesome!! thanks alot!!
     
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