How conductors/resistors affect electric fields?

In summary, an ideal conductor with zero resistance would allow charge to flow unimpeded from one terminal to another, regardless of the distance between the terminals and the electric field strength at any point. This is because the potential difference between the terminals remains the same, regardless of the field strength or length of the conductor. In contrast, in an insulating material, the opposing dipoles in the molecular structure counteract the electric field, preventing it from penetrating the material. In a resistor, the opposing dipoles also lower the net field strength, causing the current to be lower than expected. Superconductors, which have no resistance at extremely low temperatures, may also eliminate the effects of opposing dipoles.
  • #1
kostoglotov
234
6
Disclaimer: I'm not sure if this is the correct forum.

An ideal conductor (ideal = no resistance) is essentially taking the electric field at one terminal and connecting it to the other terminal. Charge moves when it is in an electric field, electric field strength is in Volts per meter, or Newtons per Coulomb. But a zero resistance conductor would appear to an electric field like no distance at all between two terminals at different potentials...(?) So the charge would flow unimpeded from one terminal to another in an electric field of field strength which we would think about as being Newtons per Coulomb. Our ideal conductor has a constant electric field strength throughout, and how long our ideal conductor is wouldn't matter, but would it not matter because (i) the ratio of potential difference to distance multiplied by the distance just gives the potential difference between the terminals regardless of the field strength at any point in an ideal conductor of any given length, and so therefore the Newtons per Coulomb measure of the field that is lower in a longer conductor is also multiplied by a greater distance to give the same Joule per Coulomb difference in potential between the terminals. Or (ii) we can forget about the Volts per Meter in an ideal conductor and just think of it as recreating the potential of the higher terminal at every point throughout its length until it reaches the lower terminal...(?)

So, as the charge flows from one terminal to another, is it continuously converting its higher terminal potential energy into "kinetic" energy until it reaches the lower terminal at 0 volts (0 is a reference only I understand)? That seems more intuitively right.

I am aware that, though they are all measured in Ohms, there are some conceptual differences between resistance, reactance and impedance. I am also aware that in an insulating material, the opposing dipoles setup in the molecular structure of the insulator in the presence of an electric field are strong enough to basically counteract the electric field before the field can penetrate the insulator.

Are the opposing dipoles in a resistor (or other resistive material) lowering the net field strength, so that the lower terminal (or some point near the lower terminal) sees a weaker field strength than it otherwise would?

Is this why putting say 3 light bulbs in series that are 30, 40 and 50 W @ 120V (and correspondingly 480, 360 and 288 ohm), will cause the actual power output of the bulbs to be nearer to 5, 4 and 3 W @ 120V each? Ie, the resistance of the elements impedes the communication of field strength between the terminals, meaning the charge itself is experiencing a lower field strength, even as it leaves the higher terminal, applying less force to the charge...but that wouldn't explain why the current is lower...so is the current lower due to another effect, say the electrons bumping messily around inside the resistor, causing a momentary back current, that smooths out quickly, applying some back pressure at the higher terminal, causing less current to leave whilst still maintaining the same voltage at the higher terminal...? Only certain materials are superconductive near at extremely low temperatures, is this because despite eliminating the resistive effects of the electrons chaotic motions there is still an opposing dipole in most materials, or would opposing dipoles be eliminated in any conductive material near absolute zero but the effect of electrons bumping around still create resistance (and superconductors somehow do away with this)?
 
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  • #2
Yes.
 

FAQ: How conductors/resistors affect electric fields?

How do conductors affect electric fields?

Conductors, such as metals, allow for the easy flow of electrons and therefore have a significant impact on electric fields. When a conductor is placed in an electric field, the free electrons within the conductor will move in response to the field, creating a new electric field within the conductor that opposes the external field. This results in a redistribution of charges and a decrease in the strength of the external electric field.

What is the role of resistors in electric fields?

Resistors, on the other hand, inhibit the flow of electrons and therefore have a different effect on electric fields. When a resistor is placed in an electric field, it will resist the flow of current and therefore cause a drop in voltage within the field. This results in a decrease in the strength of the electric field in the region of the resistor.

How do conductors and resistors differ in their effect on electric fields?

The main difference between conductors and resistors in their effect on electric fields is that conductors allow for the flow of electrons while resistors resist the flow of electrons. This results in a decrease in the strength of the electric field in the region of the conductor and a decrease in the strength of the electric field in the region of the resistor.

Can conductors and resistors be used to manipulate electric fields?

Yes, both conductors and resistors can be used to manipulate electric fields. By strategically placing conductors and resistors in an electric field, the strength and direction of the field can be altered to suit specific needs. For example, conductors can be used to shield certain areas from the effects of an electric field, while resistors can be used to create voltage drops in specific regions of the field.

How does the shape of a conductor or resistor affect its impact on an electric field?

The shape of a conductor or resistor can greatly affect its impact on an electric field. For conductors, the electric field is strongest at sharp points and edges, so a pointed conductor will have a greater effect on the field compared to a rounded one. For resistors, the length and thickness of the resistor can impact the amount of resistance and therefore the drop in voltage within the field. Additionally, the placement and arrangement of multiple conductors and resistors can also affect the overall impact on the electric field.

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