Permitivity electric field relation

In summary, the conversation discusses the relationship between electric field (E) and permittivity (ε), which is defined as the measure of a material's ability to resist the formation of an electric field within it. It is noted that E is inversely proportional to permittivity, meaning that as permittivity increases, the electric field decreases. However, this is contradicted by sources that state that higher permittivity leads to a stronger electric field due to polarization effects. The question is raised about the correct explanation for this discrepancy.
  • #1
efe
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Hi,

D=εE, and E=Q/(4πεr^2). We may suppose generally that, E is inverse proportional to permittivity. Combining the interpretation to the first equation, E is dependent variable, and D is the independent variable. That is, D is medium dependent. Anyway, E is dependent on the permittivity characteristic of the medium and this relation is inverse. Due to this inverse relation, we would expect that for mediums with higher permittivity, same configuration of charges will have smaller electric field(where D will not change).

However it says, "The larger the tendency for charge distortion (also called electric polarization), the larger the value of the permittivity." in "http://www.britannica.com/EBchecked/topic/452314/permittivity" and it says "More electric flux exists in a medium with a high permittivity (per unit charge) because of polarization effects." in "http://en.wikipedia.org/wiki/Permittivity". Due to these explanations, higher permitivity is allowing more electric flux can be generated, which implies stronger electric field. Therefore according to these, E is direct proportional to permittivity.

I am missing a point,probably an easy and a basic one, but i don't know which. So what is the correct explanation?

Thank you.
 
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  • #2
I made a mistake in:
"D is medium dependent"
I correct it to:
"D is medium independent"
 

1. What is the definition of permitivity?

Permitivity, also known as electric constant, is a measure of a material's ability to store an electric field within it. It is represented by the symbol ε and is measured in farads per meter (F/m).

2. How is permitivity related to electric field?

The permitivity of a material determines the strength of the electric field that can be sustained within it. It is directly proportional to the electric field, meaning that as the electric field increases, so does the permitivity. This relationship is represented by the equation ε = E/D, where E is the electric field and D is the electric displacement.

3. What is the significance of permitivity in electronic devices?

Permitivity plays a crucial role in the design and functioning of electronic devices. It affects the capacitance, or the ability to store electric charge, of a material. Higher permitivity materials are used in capacitors to increase their capacitance and store more charge, while lower permitivity materials are used as insulators to prevent the flow of electric current.

4. How does temperature affect the permitivity of a material?

The permitivity of a material is dependent on temperature. In general, the permitivity of most materials decreases with increasing temperature. This is due to the increased thermal motion of molecules, which disrupts the alignment of electric dipoles and reduces the material's ability to store an electric field.

5. Can the permitivity of a material be changed?

Yes, the permitivity of a material can be changed by altering its physical properties or by applying an external electric field. Materials such as dielectrics can have their permitivity increased by aligning their electric dipoles in a specific direction. This is commonly used in capacitors to increase their capacitance. Additionally, the permitivity of a material can also be affected by impurities or defects within the material.

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