Ranking the E-field from a graph alittle confused.

In summary, Figure 24-27 displays the electric potential V as a function of x. In order to rank the five regions according to the magnitude of the x component of the electric field within them, we must look at the slope of V(x). The greater the slope, the greater the absolute value of the electric field. Attempts to rank the regions based on length or area under the curve resulted in incorrect rankings.
  • #1
mr_coffee
1,629
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:
 
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  • #2
[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].
 
  • #3
Awesome! thanks alot!
 

1. How do you determine the E-field from a graph?

To determine the E-field from a graph, you can use the formula E = ΔV/Δx, where ΔV is the change in potential and Δx is the distance along the graph. This will give you the magnitude of the E-field at a specific point on the graph.

2. What does the slope of the graph represent?

The slope of the graph represents the strength of the electric field. A steeper slope indicates a stronger E-field, while a flatter slope indicates a weaker E-field.

3. How can you tell the direction of the E-field from the graph?

The direction of the E-field can be determined by the direction of the slope on the graph. If the slope is positive, the E-field is pointing in the positive direction, and if the slope is negative, the E-field is pointing in the negative direction.

4. What units are used to measure the E-field?

The E-field is measured in units of volts per meter (V/m) in the SI system, or newtons per coulomb (N/C) in the CGS system.

5. How can you compare the E-field at different points on the graph?

The E-field at different points on the graph can be compared by looking at the magnitude of the slope at each point. The larger the slope, the stronger the E-field at that point.

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