# What is Relative permittivity: Definition and 23 Discussions

The relative permittivity, or dielectric constant, of a material is its (absolute) permittivity expressed as a ratio relative to the vacuum permittivity.
Permittivity is a material's property that affects the Coulomb force between two point charges in the material. Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum.
Likewise, relative permittivity is the ratio of the capacitance of a capacitor using that material as a dielectric, compared with a similar capacitor that has vacuum as its dielectric. Relative permittivity is also commonly known as the dielectric constant, a term still used but deprecated by standards organizations in engineering as well as in chemistry.

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1. ### Relative Permitivity of Black Paint | Hi Thank You!

Hi i want to know what is the relative permitivity value of black paint. Thank you.
2. ### Connection between relative permittivity and bandwidth

What is the connection of relative permittivity and bandwidth of an antenna? Higher relative permittivity resulted in high wider bandwidth?
3. ### Theoretical ξr of a molecule from the absolute configuration

I am wondering if anybody knows how to calculate the theoretical relative permittivity of a molecule (1) using the theoretical configuration and values that are easily accessible (2). I am also wondering what the technique would be. In my pharmaceutical reaction class and also O-chem 2 we have...
4. ### How charge density of plate is changed by permittivity

Homework Statement Distance between plates of a parallel-plate vacuum capacitor is d. The capacitor is attached to a battery that keeps it at a voltage V. The space between plates is now filled dielectric relative permittivity epsilon. How will charge density of the plates change? Homework...
5. ### High K material in High frequency

Hello all I need a high K material to cancel out E-field in some direction (induced by electromagnetism). This high K material (above 5000) must work in high frequencies above 10MHz. I did use the ceramics but there is no clue that it will work in that range of frequencies or not. I am really...
6. ### I Data needed: Relative permittivity of air

Where can I found values of the relative permittivity of air at different temperatures, frequencies, pressure, humidity, etc. or its dependence? I'm particularly interested in data around 1.4 GHz, 25ºC, 1 atm. 50% hum. Thanks in advance.
7. ### Interpret current density in plasma as material property?

Homework Statement An electromagnetic wave propagates through a gas of N free electrons per unit volume. Neglecting damping, show that the index of refraction is given by n^2 = 1 - \frac{\omega_P^2}{\omega^2}, where the plasma frequency \omega_P = \sqrt{\frac{Ne^2}{\epsilon_0m_e}}.\quad(1)...
8. ### Do the Relative Permittivity and Refractive Index of Water Match Up?

Many textbooks and online sources give the relative permittivity of water as about 80 and the refractive index as 1.33. If you use the definition of refractive index to find the speed of light in water, you will find v = c/n ~ 2.56e8 m/s. However, if you use the equation to find the speed of...
9. ### Why do we multiply permittivity of vacuum with relative permittivity?

Why do we multiply permittivity of vacuum with relative permittivity? What does this calculation mean?
10. ### How Should Relative Permittivity Be Applied in Electric Field Calculations?

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...
11. ### Relative permittivity of a semiconductor material

http://physics.stackexchange.com/questions/156708/can-the-relative-permittivity-of-a-semiconductor-material-be-lower-than-1 To measure the relative permittivity of a p-type semiconductor material (a metal phthalocyanine ) , a M-S-M structure was made by thermal evaporation method. The...
12. ### How Can Relative Permittivity Be Measured in the Stratosphere?

So I am a 17 years old student who is interested in electronics and programming them (I am expirienced with Arduino). I and my friends decided that we will join a competition for all technical schools in my country. The goal of the competition is to make a project that will do something while it...
13. ### Find the relative permittivity

Consider a commonly-used capacitor made from two circular parallel plates with a ceramic dielectric between them. The plates have 12.5 mm diameter and the whole thing is 3 mm thick with a capacitance of 10 nF. Neglecting the finite thickness and extent of the plates, what relative permittivity...
14. ### Relative Permittivity: Exploring Static Charge & Capacitance

Hello forum members, I am trying to wrap my head around the concept of relative permittivity. I have read the Wikipedia article on the subject, but I don't feel quite satisfied. As far as I understand it, RP is essentially a measure of how well a given material holds a static charge relative to...
15. ### Change of relative permittivity of liquid and solid water

Dear Physics Forum Users Commonly, the relative permittivity of liquid water is reported to be \epsilon_r = 78.0\epsilon_0, \epsilon_0 being the dielectric constant of the vacuum. For ice (solid water), \epsilon_r = 4 \epsilon_0 (heard it in a talk once). Is it correct to interpret the...
16. ### Can there be a material with relative permittivity < 1?

Just a thought experiment... Cover a metal plate with a material of relative permittivity 0 on one side. Then place a charge on the metal plate. The system as a whole will accelerate towards the metal side since there is no flux on the covered side and so the charge is accelerated in the...
17. ### How to compute complex relative permittivity

Greetings. I don't know how to use an equation with a complex frequency term, specifically this one (aka Debye expression) for frequency-dependent permittivity: epsilon(omega) = epsiloninfinity + delta-epsilon/(1 + j*omega*tau) where epsilon(omega) is the permittivity at omega angular...
18. ### Relative permittivity of a conductor

Homework Statement Is the relative permittivity (ie.dielectric constant) of a conductor (metal) zero,or,infinity? Prof. Jaiswal in his golden physics (for XII std. CBSE) states that it is "zero". Another author Prof. Mohindroo in his book based on the same XII std. CBSE physics syllabus...
19. ### Relative permittivity of vacuum aluminum interface?

funny but I could not reach the info from net quickly.
20. ### Relative permittivity of gold at radio-frequencies

What is the relative permittivity of gold at radio-frequencies or specifically around 15-20MHz?
21. ### Different dielectric material with different relative permittivity

I am wondering how to different dielectric material with different relative permittivity behave when put together. Say i have two concentric sphere and the space between them is filled with a dielectric of relative permittivity A from the outer surface of the inner sphere to the mid point...
22. ### Relative Permittivity and Refractive Index

in relating the index of refraction to the relative permittivity (dielectric constant/function). it is known that n = \sqrt{\epsilon_r} for optical frequencies (i.e. \mu_r=1. now this website http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/diel.html#c1 gives the relative permittivity of...
23. ### Dielectrical constant / relative permittivity

Hi! Im woundering if the relative permittivity in a capacitor is dependent on the level of charge in the capacitor? /Nikke.