Irodov – Problems in General Physics

17. Permittivities

(relative values)

Dielectric a Dielectric a

Water^81 Mica 7.5

Air 1.00058 Alcohol^26

Kerosene 2.0 Glass 6.0

Paraffin 2.0 Porcelain 6.0

Plexiglas 3.5 Ebonite 2.7

Polyethylene 2.3

18. Resistivities of Conductors

Conductor Resistivity (at 20 °C) p, nid•m

Temperature coefficient

a, kK-1^

Aluminium^25 4.5

Tungsten^50 4.8

Iron^90 6.5

Gold^20 4.0

Copper^16 4.3

Lead^190 4.2

Silver^15 4.1

19. Magnetic Susceptibilities of Para- and Diamagnetics

Paramagnetic sub-

stance u.-1,^ 10-^6

Diamagnetic sub-

stance p.-1,^10 -6^

Nitrogen 0.013 Hydrogen —0.063

Air 0.38 Benzene —7.5

Oxygen 1.9 Water —9.0

Ebonite^14 Copper —10.3

Aluminium^23 Glass —12.6

Tungsten^176 Rock-salt —12.6

Platinum 360 Quartz —15.1

Liquid oxygen^3400 Bismuth —176

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