Why Does Polythene Show Different Permittivity Values in Experiments?

  • Thread starter QuantumCrash
  • Start date
  • Tags
    Permittivity
In summary, the experiment to find the relative permittivity of polythene resulted in a value of 1.57, which differs significantly from the commonly accepted value of 2.35. Potential sources of error include non-uniformity of the polythene sheet, imperfections in the metal plates, and air gaps between the plates and the polythene. Further investigation and careful control of these factors may lead to more accurate results in future experiments.
  • #1
QuantumCrash
135
0
Hi, recently my class did an experiment to find the relative permittivity of polythene. I did some calculations by comparing the capacitance of 2 metal plates with air between them and the same capacitor with a sheet of polythene. It turned oout to be 1.57. However, I googled and it seemed to be 2.35 instead.

Can you suggest what might actually have caused this error? There seems to be many possible reasons like slight fluctuations in the current or even increase of resistance in the wire due to heating but none seems to explain such a large difference.
 
Physics news on Phys.org
  • #2
There could be several reasons for the difference in your results. First, it is possible that the sheet of polythene you used was not uniform in thickness or surface area. If this was the case, then the capacitance would be affected and could lead to an inaccurate result. Secondly, if the metal plates were not perfectly flat, then the capacitance could also be affected and lead to inaccurate results. Finally, any air gaps between the metal plates and the polythene could also affect the capacitance and lead to an inaccurate result.
 
  • #3


Hello,

Thank you for sharing your experiment with me. The permittivity of polythene is an important property to understand, and it is great that you and your class were able to investigate it.

Based on your calculations, you found a relative permittivity of 1.57 for polythene, while the literature suggests a value of 2.35. This difference could be due to several factors, such as experimental error, variations in the materials used, or limitations of the equipment.

One possible explanation for the discrepancy could be errors in measurement. It is important to ensure that all measurements are taken accurately and consistently. Any small variations in the measurements can lead to significant differences in the final result.

Additionally, the materials used in the experiment may not have been exactly the same as those used in the literature. It is important to use standardized materials and methods in order to obtain reliable results.

Another factor that could have influenced the results is the limitations of the equipment used. The accuracy and precision of the equipment can affect the final result. It is important to calibrate and use high-quality equipment for accurate measurements.

In conclusion, it is difficult to pinpoint the exact cause of the discrepancy without further information. I would suggest repeating the experiment multiple times and taking extra care in measurements and using standardized materials and equipment to ensure accurate results. I hope this helps. Keep up the good work!
 

Related to Why Does Polythene Show Different Permittivity Values in Experiments?

1. What is the permittivity of polythene?

The permittivity of polythene, also known as the dielectric constant, is a measure of the ability of the material to store electrical energy in an electric field. It is typically represented by the symbol ε and has a value of about 2.25 for polythene.

2. How does the permittivity of polythene affect its electrical properties?

The higher the permittivity of a material, the more easily it can store electrical energy. This means that polythene has a higher capacitance, or ability to hold an electric charge, compared to other materials with lower permittivity values.

3. How is the permittivity of polythene measured?

The permittivity of polythene can be measured using a device called a capacitance meter. This instrument measures the capacitance of a material, which is directly related to its permittivity.

4. Does the permittivity of polythene change with temperature?

Yes, the permittivity of polythene is temperature-dependent. As the temperature increases, the permittivity also increases, meaning that the material becomes better at storing electrical energy.

5. Are there other factors that can affect the permittivity of polythene?

Yes, the permittivity of polythene can also be influenced by factors such as the type of polythene, its thickness, and any impurities or additives present in the material. These factors can cause slight variations in the permittivity value for polythene.

Similar threads

  • Introductory Physics Homework Help
Replies
9
Views
10K
  • Introductory Physics Homework Help
Replies
1
Views
3K
  • Introductory Physics Homework Help
Replies
4
Views
1K
Replies
46
Views
2K
  • Classical Physics
Replies
1
Views
781
  • Mechanical Engineering
Replies
28
Views
2K
Replies
13
Views
2K
Replies
16
Views
2K
  • Electrical Engineering
Replies
7
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
6K
Back
Top