Changing the k constant in voltage potential equation?

In summary, the conversation discusses calculating voltage potential for a dipole underwater and the need to change the k constant, which represents the vacuum permittivity. The speaker suggests using the relative permittivity of the material and mentions the impact of temperature and impurities on conductivity. They also consider the difference between fresh and salt water in terms of conductivity.
  • #1
falconblade
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Summary:: What if you were calculating the voltage potential for a dipole, but underwater?

I'm making a predictive model (in R programming) for the voltage potential at any point around a dipole. I need to be able to change parameters, one being the k constant.

V=( kpcosѲ)/(r^2).
Where V is voltage, k is the constant (N m^2/C^2), p is the dipole moment (p=qd), and r is pretty much the distance.
(attaching a page from textbook over this)

I need the k constant changed because I am simulating this underwater, with conductivity (μS/cm) taking the place of my k constant. Any ideas on how to approach this? Far fetched but, is there a way to convert μS to N m^2/C^2?
 

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  • #2
The constant you are trying to change is $$k=\frac{1}{4\pi\epsilon_0}.$$ Where ##\epsilon_0## is the vacuum permittivity. To use the dipole equation in a material you need to multiply ##\epsilon_0## by the relative permittivity of the material ##\epsilon_r##.

For water at 20 degrees Celsius, ##\epsilon_r\approx 80##. Be aware, though, that it is very temperature dependent. It also sounds like you have impurities causing conductivity, so that's likely going to change the value too.
 
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  • #3
falconblade said:
Summary:: What if you were calculating the voltage potential for a dipole, but underwater?

Summary:: What if you were calculating the voltage potential for a dipole, but underwater?

I'm making a predictive model (in R programming) for the voltage potential at any point around a dipole. I need to be able to change parameters, one being the k constant.

V=( kpcosѲ)/(r^2).
Where V is voltage, k is the constant (N m^2/C^2), p is the dipole moment (p=qd), and r is pretty much the distance.
(attaching a page from textbook over this)

I need the k constant changed because I am simulating this underwater, with conductivity (μS/cm) taking the place of my k constant. Any ideas on how to approach this? Far fetched but, is there a way to convert μS to N m^2/C^2?
Is it fresh or salt water?
If salt you aso need to consider conductivity which is very large in salt water whch consists mostly of ionized sodium and chlorine.
If fresh conductivity might be low enough to ignore, depends again on the salinity of the water.
 
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1. How does changing the k constant affect the voltage potential equation?

Changing the k constant in the voltage potential equation affects the magnitude of the electric field. The higher the value of k, the stronger the electric field will be, and vice versa. This is because the k constant represents the permittivity of the medium, which determines how easily electric charges can move through it.

2. Can changing the k constant change the direction of the electric field?

No, changing the k constant does not change the direction of the electric field. The direction of the electric field is determined by the relative positions and charges of the objects involved, not by the permittivity of the medium. However, changing the k constant can affect the strength of the electric field, which can indirectly impact its direction.

3. How is the k constant related to the Coulomb's law constant?

The k constant is directly related to the Coulomb's law constant. In fact, the Coulomb's law constant is equal to 1/4πε0, where ε0 is the permittivity of free space. This means that the value of the k constant depends on the medium in which the electric charges are interacting.

4. What happens to the voltage potential if the k constant is doubled?

If the k constant is doubled, the voltage potential will also double. This is because the voltage potential is directly proportional to the k constant. Therefore, increasing the value of k will result in a stronger electric field and a higher voltage potential.

5. Is it possible to have a negative value for the k constant?

Yes, it is possible to have a negative value for the k constant. This would occur in a medium with a negative permittivity, such as certain types of materials or in the presence of a dielectric. However, in most cases, the k constant will be positive, as most materials have a positive permittivity.

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