Capacitance vs. Distance of separation

In summary, the conversation discusses the topic of capacitance vs. distance of separation and the correct way to graph this relationship. The discussion touches upon the relationship being inversely proportional and the direction of the slope on the graph. The expert concludes that the graph with a positive slope is correct and explains the reasoning behind why capacitance is inversely proportional to distance.
  • #1
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[SOLVED] Capacitance vs. Distance of separation

Homework Statement



Hi, I am suppose to make a capacitance vs (1/d) graph. I understand that the relationship between the capacitance and distance between the plates is inversely proportional and that it does not produce a straight line.
My instructor mentioned that when graphing the C vs 1/d graph it would have a negative slope, but when plotting the point in excel I get a graph with positive slope.

The Attempt at a Solution



y2nn4.jpg

1/d is on the x-axis and C is on the y axis. Does this graph seem correct, or should I go with the graph that has the negative slope which I can only get by using a C vs d relationship.
 
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  • #2
In general the independent variable (the variable which you are controlling) is plotted on the x-axis and the dependent variable (the variable that you are measuring) is plotting on the y-axis. So assuming that you varied that distance and measured the capacitance (as I imagine you did), then your plot is correct.

Since (as you correctly say), [itex]C\propto 1/d[/itex] and all of the constants are positive, your gradient will also be positive. Perhaps your instructor misspoke or you misheard.
 
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  • #3
thank you for your help.
 
  • #4
1/D is not intuituve

I grant you the formula for determining capacitance, but I would think that increasing distance would increase the ability of the plates to hold charge as it would increase the insulation of the dielectric and thus decrease the possibility of short across the dielectric and thus increasing the voltage across the plates. Why is C inversely proportional to distance and not directly proportional?
 

Related to Capacitance vs. Distance of separation

1. What is capacitance?

Capacitance is a measure of an object's ability to store electrical charge. It is determined by the size, shape, and distance between two conductive plates or objects.

2. How does capacitance change with distance of separation?

As the distance between two conductive objects increases, the capacitance decreases. This is because the electric field between the objects weakens, reducing the ability to store charge.

3. What is the relationship between capacitance and distance of separation?

Capacitance and distance of separation have an inverse relationship, meaning that as one increases, the other decreases. This relationship is described by the equation C = εA/d, where C is capacitance, ε is the permittivity of the material between the objects, A is the surface area of the objects, and d is the distance of separation.

4. How does the shape of the conductive objects affect capacitance vs. distance of separation?

The shape of the conductive objects can affect capacitance by altering the surface area and distance of separation between the objects. For example, two parallel plates will have a larger capacitance than two spherical objects with the same distance of separation, as the plates have a larger surface area.

5. How is capacitance vs. distance of separation used in practical applications?

Capacitance vs. distance of separation is used in a variety of applications, such as in capacitors, touch screens, and proximity sensors. It is also an important concept in understanding and designing electronic circuits and systems.

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