How Should Relative Permittivity Be Applied in Electric Field Calculations?

In summary, the conversation discusses the proper use of relative permittivity (εr) in calculating electric field strength between two point charges in a medium. The speaker is unsure whether to multiply εr by the permittivity of free space (εo) or to use it differently. It is mentioned that εo and εr are always used together, and some formulas explicitly show their product while others denote it as ε.
  • #1
Jmphysics
1
0

Homework Statement


I've been given a question where I have to find the electric field strength at a point between two charges. Now I understand the mathematics but the question I'm trying to solve says two point charges of value 2C and 3C are position within a medium of relative permittivity 5.5.

My question is when i put my values into the electric field strength equation should this value 5.5 be multiply by the permittivity of free space or be used differently.

Homework Equations

The Attempt at a Solution


I have looked on the internet for the formula but sometimes its written differently and I just want to be one hundred percent confident I'm using this value correctly since I keep finding conflicting information.
 
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  • #2
It is strange that it's worded like that, but my guess is that you multiply the permittivity of free space by 5.5
 
  • #3
Hi Jmphysics.
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εo and εr always go around together like a married couple; where you find one it needs the other right alongside.

Some formulae emphasise this by explicitly showing their product εoεr, other formulae denote this product concisely as just ε
 

Related to How Should Relative Permittivity Be Applied in Electric Field Calculations?

1. What is relative permittivity?

Relative permittivity, also known as dielectric constant, is a measure of a material's ability to store electrical energy in an electric field.

2. How is relative permittivity different from permittivity?

Relative permittivity is a dimensionless quantity that compares the permittivity of a material to the permittivity of a vacuum. Permittivity, on the other hand, is a physical constant that measures the resistance of a material to the formation of an electric field.

3. How is relative permittivity measured?

Relative permittivity is measured by placing a material between two parallel plates, applying a known electric field, and measuring the capacitance of the material. The ratio of the material's capacitance to the capacitance of a vacuum is the relative permittivity.

4. What factors affect the relative permittivity of a material?

The relative permittivity of a material is affected by factors such as temperature, pressure, and the presence of impurities or defects in the material. It can also vary depending on the frequency of the electric field applied to the material.

5. Why is relative permittivity important in materials science?

Relative permittivity plays a crucial role in determining the electrical properties of materials. It is used in the design and development of electronic devices and plays a significant role in the behavior of insulators and capacitors. Understanding relative permittivity is essential in many areas of materials science, including nanotechnology, energy storage, and telecommunications.

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