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 axis

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 axis

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