8. Relative permittivity
Dielectric constant is the coefficient that shows the relation between the electric charge and the force provided by it within a material. A material has respective intrinsic dielectric constant. This value is determined by how the atom (or molecule) in a material responds when electrical field is provided from the external. In other words, dielectric constant is determined by how the dielectric polarization is generated. Kε which is the ratio of dielectric constant ε and electrical constant of a material is called Relative permittivity. Relative permittivity changes by temperature t and frequency f. Moreover, established a relation called as expressed the Relative permittivity by complex number, and found loss angle of the dielectric loss.
solid | ||||
---|---|---|---|---|
Material | Temperature t℃ | Number of vibration fHz | Relative permittivitykε | ![]() |
Paraffin |
20 |
![]() |
2.2 |
2 |
Amber |
20 |
![]() |
2.8-2.6 |
2-90 |
Fused quartz |
20-150 |
![]() |
3.8 |
10-1 |
![]() |
25 |
![]() |
332 |
|
Crystal |
20 |
![]() |
4.5 |
|
KCl |
20 |
![]() |
4.8 |
5-1 |
Daimond |
20 |
500-3000 |
5.68 |
|
NaCl |
25 |
![]() |
5.9 |
2 |
Steatite |
20 |
![]() |
6 |
2-20 |
Fluorite |
20 |
![]() |
6.8 |
|
Lead glass |
20 |
![]() |
6.9 |
17-13 |
Mica |
20-100 |
![]() |
7.0 |
10-2 |
Soda glass |
20 |
![]() |
7.5 |
100-80 |
Alumina |
20-100 |
![]() |
8.5 |
20-5 |
Rubber (Silicone) |
20 |
![]() |
8.6-8.5 |
50-10 |
Sapphire |
20 |
![]() |
9.4 |
2 |
Fluid | |||
---|---|---|---|
![]() |
![]() |
Relative permittivitykε | ![]() |
Liquid helium |
4.19K |
1.048 |
|
Liquid hydrogen |
20.4K |
1.23 |
-280 |
Liquid nitrogen |
70K |
1.45 |
-200 |
Liquid oxygen |
80K |
1.51 |
-160 |
Liquid argon |
82K |
1.53 |
-220 |
Carbon tetrachloride |
20 |
2.24 |
-90 |
Benzene |
20 |
2.284 |
-85 |
Toluene |
20 |
2.39 |
-100 |
Carbon bisulfide |
20 |
2.64 |
-100 |
Acetone |
25 |
20.7 |
-470 |
Ethyl alchol |
25 |
24.3 |
|
Methyl alcohol |
25 |
32.6 |
-600 |
Nitrobenzene |
25 |
34.8 |
-520 |
*1 It will be described by when the Relative permittivity kε of water is t℃.
*2 The K within the column of Temperature t shows the absolute temperatureKelvin.
Gas | ||
---|---|---|
Material1atm | Temperature t℃ | ![]() |
Argon |
20 |
5.17 |
Ammonia |
1 |
71 |
Ethyl alcohol |
100 |
78 |
Oxygen |
20 |
4.94 |
Hydrogen |
0 |
2.72 |
Water vapour |
100 |
60 |
Nitrogen |
20 |
5.47 |
Carbon dioxide |
20 |
9.22 |
Sulfur dioxide |
22 |
82 |
Carbon disulfide |
29 |
29.0 |
Helium |
0 |
0.7 |
Benzene |
100 |
32.7 |
Methyl alcohol |
100 |
57 |