Calculate the dielectric constant of the material

In summary, the conversation involves the calculation of the dielectric constant of a material based on the force exerted by two point charges in free space. The initial force is 2.6 nN and when the free space is replaced by a homogeneous dielectric material, the force becomes 1.5 nN. Through the use of equations and computations, the dielectric constant is determined to be 1.73. There is a discussion about the use of relative dielectric constant versus the actual dielectric constant, as well as the conversion of nano Newtons to Coulombs/m^2N^2. It is advised to use the ratio of forces rather than numerical computations to determine the dielectric constant.
  • #1
DODGEVIPER13
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Homework Statement


two point charges in free space are separated by distance d and exert a force 2.6 nN on each other. The force becomes 1.5 nN when the free space is replaced by a homogeneous dielectric material. Calculate the dielectric constant of the material.


Homework Equations


I used an equation but i did not write it down so I am not totally sure what I used


The Attempt at a Solution


2.6=(9E9)Q^2/d^2 then Q=.000016997d then 1.5=(.000016997d)^2(9e9)/(epsilonr) then epsilonr=1.73 now I have a couple of problems with what I did first I believe I have only found for the relative dielectric constant rather than the dielectric constant. An the second problem is that I did not convert nano Newtons to Columbs/m^2N^2 as I wasnt sure of the conversion I searched on google and couldn't find it?
 
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  • #2
The two charges aren't necessarily of the same strength (in Coulombs) so don't bother trying to compute them.

Still, what you did was OK. The answer is εr = 1.73.

The force is kq1*q2/d^2 but k = 1/4πε. In vacuo ε = ε0 = 8.855e-13 F/m and er = 1.

In the dielectric er = 1.73 as you have computed, and ε = 1.73ε0.

Also never mind computing forces numerically. All you need is Fvacuum/Fdielectric = 1.73.
 
  • #3
Cool so my answer was good for once
 

Related to Calculate the dielectric constant of the material

1. What is the dielectric constant of a material?

The dielectric constant, also known as the relative permittivity, is a measure of a material's ability to store electrical energy in an electric field. It is a dimensionless quantity and is defined as the ratio of the electrical permittivity of the material to the electrical permittivity of vacuum.

2. How is the dielectric constant of a material calculated?

The dielectric constant of a material can be calculated by measuring the capacitance of a parallel plate capacitor with the material as the dielectric, and comparing it to the capacitance of a vacuum capacitor with the same dimensions. The dielectric constant is then equal to the ratio of these two capacitances.

3. What factors affect the dielectric constant of a material?

The dielectric constant of a material is affected by various factors such as temperature, frequency, and the presence of impurities. In general, the dielectric constant increases with increasing temperature and decreases with increasing frequency. The presence of impurities can also alter the dielectric constant of a material.

4. Why is the dielectric constant important?

The dielectric constant is an important property of materials in the field of electromagnetics. It affects the electric field strength, capacitance, and other electrical properties of materials. It is also used in the design and optimization of electronic devices and circuits.

5. Can the dielectric constant of a material change over time?

Yes, the dielectric constant of a material can change over time due to various factors such as exposure to moisture, temperature changes, and mechanical stress. This can affect the performance of electronic devices and should be taken into consideration during their design and operation.

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