Radial dependencies with electric field

In summary, the electric field strength for a point "r" from the center of a ring of charge is inversely proportional to the square of the distance, while for a long line of charge it is inversely proportional to the distance. This is due to the difference in the distribution of charge and the resulting shape of the electric field. As the distance from the charge increases, the ring of charge appears more like a point charge and therefore follows the inverse square rule, while the line of charge maintains its linear dependency. The electric field near an infinite plane of charge remains constant, regardless of the distance, due to the constant size of the charged planes at different distances.
  • #1
kiwibird4
8
0
so for uniform charge densities, a point "r" from the center of a ring of charge has an
E ∝ 1/r^2
a point "r" from center of a long line of charge has an
E ∝ 1/r
and for an infinite plane, a point "r" from it where r<<length of plane has
E not dependent on r

my question was why is it that a ring of charge has an inverse square proportionality compared to a line of charge? Does the point have a stronger dependency on distance because there is "more area" of a ring then simply a line's electric field?

Also, when I think about r becoming extremely large (so the point is very far away), wouldn't the ring of charge be more like a point charge but why would the line be seen less as a point charge since it is not an inverse squared dependency but an inverse linear dependency (if that even makes any sense)
 
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  • #2
For a ring of charge, when up close, the available charge would be producing an electric field in an ever growing series of nested cylinders. The area of the cylinders growing by the equation 2*r*pi.The drop off in field strength would thus be linear. As the ring receeds in the distance, it appears as a receeding point, thus the charge must be supporting a series of nested spheres, growing in surface area by 4*pi*r^2. The electric field thus dropping off by the inverse square rule. For the field near an infinite plane of charge, the charged plane supplies planes of the same size as the distance increases thus the field strength does not change.
 

Related to Radial dependencies with electric field

1. What is a radial dependency with electric field?

A radial dependency with electric field refers to the relationship between the strength of an electric field and the distance from the source of that field. This relationship is often described using mathematical equations and is an important concept in understanding how electric fields behave.

2. How is the strength of an electric field affected by its radial distance?

The strength of an electric field is inversely proportional to its radial distance. This means that as the distance from the source of the field increases, the strength of the field decreases. This is due to the spreading out of the field lines as they move further away from the source.

3. What is the significance of radial dependencies with electric field?

Radial dependencies with electric field are significant because they allow scientists to understand and predict the behavior of electric fields. By studying the relationship between distance and strength, scientists can determine the strength of an electric field at any given point and make calculations for various applications such as in electronics and technology.

4. How are radial dependencies with electric field measured?

Radial dependencies with electric field can be measured using instruments such as a voltmeter or an electrometer. These instruments measure the voltage or potential difference between two points in an electric field and can be used to calculate the strength of the field at different distances from the source.

5. Can radial dependencies with electric field be applied to other types of fields?

Yes, radial dependencies can also be observed in other types of fields such as magnetic fields. In fact, the strength of a magnetic field also follows an inverse relationship with distance, similar to electric fields. This concept is important in understanding and predicting the behavior of various fields in science and technology.

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