It is well known that dielectric constant of liquids/gases change with temperature, and frequency, besides some other parameters may influence it.
Can anyone comment on the following questions/confusion. Thanks a lot!
1) Why all gases possess very low dielectric constant (or from another view, very comparable values); they differ ONLY at third significant digit after decimal point? All gases are quoted with dielectric constant as "1.0000-- to 1.0----- ".
Does it reflect that all gases are easy to polarize when exposed to external electric field (the reason of it stems from the gas molecules which are not closely packed, and can aligned/orient rather easily-on a little expense of electric field). Is it correct way of thinking?
2) I found a huge variation in "dielectric constant" of Ammonia (NH3) gas (dielectric constant = 1.00622) and Liquid Ammonia (dielectric constant = 18 ~ 22). Can we trust on these values?
3) Can anyone suggest me any book/article for Loss tangents of gases (like Hydrogen, Argon, Nitrogen dioxide, Ammonia, Formaldehyde etc)
my dear ,this file maybe help you
https://en.wikipedia.org/wiki/Dielectric_gas
Dear Bilawal
I think your view is wrong. The relative dielectric constant of a gas is almost =1 which means that the gas behave almost as the vacuum.
There are two reasons:
1) The polarizability of a material (as well as the dielectric constant) depends on the particle density, and because the gas density is much lower than liquid or solid, the dielectric constant is almost 1.
2) The high mobility of molecules in the gas, in one way can facilitate orientation through electric field, but collisions, very frequent in gas phase, destroy the order in the case, vanishing the effect of the field.
In any case a gas is not a perfect insulator, but if the electric field overcome a given value you obtain a discharge and the gas become a good conductor. The electrical conductivity depends on the gas composition and also on the electric field itself. Therefore a gas behave as a semiconductor with band-gap related to the ionization potential.
Yes, primarily the density being too low in gases, the polarizing field will be very small. There will not be appreciable change from an externally applied field and net field after reducing the negligible field due to very few atoms/ molecules of the gas. The ratio of E0/E will be practically 1. And the temperature will not alter this since the effect will be much smaller.
Dear Ali, Gianpiero, and Vijay, thank you very much for valuable and detail comments.
Thanks a lot!
Dear Bilawal, could you please tell me from which book you took that table? I would like to reference it. Thanks in advance,
Dear Rita Joana da Cruz Roque, I think it is from here, but make sure:
https://books.google.es/books?id=q2qJId5TKOkC&pg=PP1322&lpg=PP1322&dq=%22permittivity+(dielectric+constant)+of+gases+(continued)&source=bl&ots=9Wc__LpdPf&sig=ACfU3U3i3fGRMaNUGgESfVCwF-m-ldzi3Q&hl=en&sa=X&ved=2ahUKEwjpuaXv7o3oAhUSyxoKHXFOBskQ6AEwDXoECAkQAQ#v=onepage&q=%22permittivity%20(dielectric%20constant)%20of%20gases%20(continued)&f=false
Dear Bilawal
Have you found an answer to your 3 year old question ?
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