Comparing Electric Potential and Electric Field

In summary, the conversation discusses the relationship between Electric Potential and Electric Field. The equation for electric potential is given as ΔV=-∫Esds and it is explained that electric potential is the negative integral of electric field. The concept of graphing both in the positive y-axis is also mentioned, with confusion about why electric field would increase when electric potential decreases. The expert summarizer explains that the electric field is the force felt by a positive charge divided by the charge and the potential is the potential energy divided by the charge. The relationship between the two is further discussed, with the expert clarifying that it is not as simple as a direct correlation between the two.
  • #1
MattyP
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Homework Statement



I guess this isn't like a homework question. I'm studying for an upcoming exam and feel pretty confident about most of the material, except for the relationship between Electric Potential and Electric Field. I guess the pertinent equation is as follows:


Homework Equations



ΔV=-∫Esds

The Attempt at a Solution



I understand the concept behind this. Electric potential is the negative integral of electric field. What confuses me is that my professor keeps graphing both in the positive y-axis. If electric potential is the NEGATIVE integral of electric field, wouldn't it always be the "opposite". So if graphing E vs distance and E = +1000 V/m at d = 20m and electric field is increasing as distance increases, wouldn't the electric field vs distance graph start at, say, some arbitrary y-value and then decrease as distance decreases?

This doesn't conceptually make sense to me anyway because of electric potential's equation. I would imagine that E would increase as V increased since the only difference in equation is that one is inverse squared and one is not.

I've derived V from E so that I would understand it mathematically as well. I guess my issue is the conceptual reasoning for it.

So to sum it up, why does E increase when V decreases

Sorry if this is redundant / been asked before. I know I'll probably be yelled at for messing something up my first time posting her, but I guess I'll learn
 
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  • #2
The electric field is the force felt by a positive charge divided by the charge.
The potential is the potential energy divided by the charge.

These two are related in that the electric field is the (negative) gradient of the potential.
The negative sign is due to the definitions: when a positive charge moves along an electric field line, it has to lose potential energy.

The sign of the potential difference depends on the reference point so what the plot looks like depends entirely on context. \

why does E increase when V decreases
The relationship is not that simple.
i.e. in a uniform electric field, you may move between positions of varying potential, yet the E field does not change at all.
http://farside.ph.utexas.edu/teaching/302l/lectures/node34.html
 

Related to Comparing Electric Potential and Electric Field

1. What is the difference between electric potential and electric field?

Electric potential (or voltage) is a measure of the potential energy per unit charge at a given point in an electric field. It is a scalar quantity, meaning it has magnitude but no direction. Electric field, on the other hand, is a vector quantity that describes the direction and strength of the force on a positive test charge at a given point in an electric field.

2. How are electric potential and electric field related?

The electric field is the negative gradient of the electric potential. In other words, the electric field at a given point is equal to the change in electric potential per unit distance in the direction of the field. Mathematically, this can be represented as E = -∇V, where E is the electric field, V is the electric potential, and ∇ is the gradient operator.

3. Which one is more important, electric potential or electric field?

Both electric potential and electric field are important in understanding the behavior of electrically charged particles. However, electric potential is often considered to be more fundamental because it is a scalar quantity and can be used to calculate the electric field at any given point. Electric field, on the other hand, is a vector quantity and can only be measured at specific points in an electric field.

4. How do electric potential and electric field affect the movement of charged particles?

Electric potential and electric field play a crucial role in determining the movement of charged particles. Charged particles will move from areas of high electric potential to areas of low electric potential, and they will experience a force in the direction of the electric field. The magnitude and direction of this force can be calculated using the equations F = qE and F = q∆V, where F is the force, q is the charge, E is the electric field, and ∆V is the change in electric potential.

5. Can electric potential and electric field be measured?

Yes, both electric potential and electric field can be measured using various instruments. Electric potential can be measured using a voltmeter, which measures the potential difference between two points in an electric field. Electric field can be measured using an electric field sensor, which measures the strength and direction of the electric field at a given point.

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