Constants and Standards
This page is prepared for HTML 4.0 browsers and uses Symbol Font, please be certain that this font is installed in your computer
DIELECTRIC CONSTANTS OF MATERIALS
The dielectric constants of most materials vary for different ternperatures and frequencies. Likewise, small differences in the composition of materials will cause differences in the dielectric constants. A list of materials and the approximate range (where available) of their dielectric constants are given in Table 21. The values shown are accurate enough for most applications. The dielectric constants of sorne materials (such as quarfz, Styrofoam, and Teflon) do not change appreciably with frequency.
Table 21 Dielectric constants of Matrials


Material  Dielectric Constants (Approx.)   Material  Dielectri Constantc (Approx.) 

Air
Amber
Asbestos Fiber
Bakelite (asbestos base)
Bakelite (mica filled)
Barium Titanote
Beeswax
Cambric (varnished)
Carbon Tetrachloride
Colluloid
Collulose Acetate
Durite
Ebonite
Epoxy Resin
Ethyl Alcohol (obsolute)
Fiber
Formica
Glass (electrical)
Glass (photogrophic)
Glass (Pyrex)
Glass (window)
Gutta Percha
Isolantite
Lucite
Mico (olectrical)
Mica (cloor Indio)
Mica (filled phenolic)
Micaglass (titanium dioxide)
Micarta
Mycolex
Neoprene

1.0
2.62.7
3.14.8
5.022
4,54.8
1001250
2.42.8
4.0
2.17
4.0
2.94.5
4.75.1
2.7
3.43.7
6.525
.0
3.66.0
3.814.5
7.5
4,65.0
7.6
2.42.6
6.1
2.5
4.09.0
7.5
4.25.2
9.09.3
3.25.5
7.39.3
4.06.7


Nylon
Poper (dry)
Paper (paraffin coated)
Paraffin (solid)
Plexiglas
Polycorbonate
Polyethylene
Polyimide
Polystyrene
Porcelain (dry process)
Porcelain (wet process)
Quartz
Quartz (fused)
Rubber (hard)
Ruby Mica
Selenium (amorphous)
Shellac (natural)
Silicone (glass) (molding)
Silicone (glass) (laminate)
Slate
Soil (dry)
Steatite (ceramic)
Steatite (low loss)
Styrofoam
TefIon
Titanium Dioxide
Vaseline
Vinylite
Water (distilled)
Waxes, Mineral
Wood (dry)

3.422.4
1.53.0
2.54.0
2.03.0
2.63.5
2.93.2
2.5
3.43.5
2.43.0
5.06.5
5.86.5
5.0
3.78
2.04.0
5.4
6.0
2.93.9
3.24.7
3.74.3
7.0
2.42.9
5.26.3
4.4
1.03
2.1
l00
2.16
2.77.5
3478
2.22.3
1.42.9

METRIC SYSTEM
The international system of units developed by the General Conference on Weights and Measures (abbreviated CGPM), commonly called the metric system, is the basis for a worldwide
Table 22. SI Base and Supplementary Units 
Quantity  Unit  Symbol 
length
mass time electric current thermodynamic temperature amount of substance luminous intensity plane angle solid angle

meter kilograrn second ampere kelvin * mole candela radiant † steradiont †

m
kg
s
A
K
mol
cd
rad
sr

* The degree Celsius is also used for expressing temperature. † Supplementory units.
Table 23. SI Derived Units With Special Names 
Quantity  Unit  Symboll  Formula 
frequency (of a periodic phenomenon)
force^{ }
pressure, stress^{ }
energy, work, quantity of heat
power, radiant flux
quantity of electricity electric charge
electric potential, potential difference, electromotive
force
capacitance
electric resistance
concluctance
magnetic flux
magnetic flux density^{ }
incluctance
luminous flux
illuminance^{ }
activity (of radionuclides)
obsorbed close

hertz
newton^{ }
pascal^{ }
joule
watt
coulomb
volt
farad
ohm
siemens
weber
tesla^{ }
henry
lumen
lux^{ }
becquerel
gray

Hz
N^{ }
Pa^{ }
J
W
C
V
F
W
S
Wb
T^{ }
H
Im
Ix^{ }
Bq
Gy

I/s
kg'm/s^{2}
N/m^{2}
N*m
J/s
A*s
W/A
C/V
V/A
AN
V*s
Wb/m^{2}
Wb/A
cd*sr
Im/m^{2}
I/s
J/kg

standardization of units. This International System of Units (abbreviated SI) is divided into three classesbase units, supplementary
units; and derived units.
Units and Symbols
The seven base units and the two supplementary units with their symbols are given in Table 22.
Derived units are formed by combining base units, supplementary units and other derived units. Certain derived units have special names and symbols. These units, their symbols and formulas, are given in Table 23. Other common derived units, and their symbols, are given in Table 24.
Table 24. Common SI Derived Units

Quantity  Unit  Symbol 
acceleration^{ }
angular acceleration^{ }
angular velocity^{ }
area^{ }
concentration (of amount of substance)^{ }
current density^{ }
density, mass^{ }
electric charge density^{ }
electric field strength^{ }
electric flux density
energy density^{ }
entropy
heat capacity
heat flux density irradiance^{ }
luminance^{ }
magnetic field strength
molar energy
molar entropy
molar heat capacity
moment of force
permeability
permittivity
radiance^{ }
radiant intensity
specific heat capacity
specific energy
special entropy
specific volume^{ }
surface tension
thermal conductivity
velocity
viscosity, dynamic
viscosity, kinernatic^{ }
volume^{ }
wovenumber^{ }

meter per second squored^{ }
radian per second squared^{ }
radion per second^{ }
square meter^{ }
mole per cubic meter^{ }
ampere per square meter^{ }
kilogram per cubic meter^{ }
coulomb per cubic meter^{ }
volt per meter
coulomb per square meter^{ }
joule per cubic meter^{ }
joule per kelvin^{ }
joule per kelvin
watt per square meter^{ }
candela per square meter^{ }
ampere per meter
joule per mole
joule per mole kelvin
joule per mole kelvin
newton meter
henry per meter
farad per meter
watt per square meter steradian^{ }
watt per steradion
joule per kilogram kelvin
joule per kilogrom
joule per kilogram kelvin
cubic meter per kilogrom^{ }
newton per meter
watt per meter kelvin
meter per second
poscal second
square meter per second^{ }
cubic meter^{ }
l per meter

m/s^{2}
rad/s^{2}
rad/s
m^{2}
mol/m^{3}
A/m^{2}
kg/m^{3}
C/m^{3}
V/m
C/m^{2}
J/m^{3}
J/K
J/K
W/M^{2}
cd/m^{2}
A/m
J/mol
J/(mol*K)
J/(mol*K)
Nm
H/m
F/m
W/(m^{2} sr)
W/sr
J/(kg*K)
J/kg
J/(kg*K)
M^{3}/kg
N/m
W/(m*K)
m/s
Pa*s
m^{2}/s
m ^{3}
I/m

Some units, not part of SI are so widely used they are impractical to abandon. These units Listed in Table 25) are acceptable for continued uses.
Table 25 Units in Use With SI 
Quantity  Unit  Symbol  Value 
Time
Plane angle
volume^{ }
Mass^{ }
Area (land)^{ }

minute
hour
day
week, month,
year
degree
minute
second
liter^{ }
metric ton^{ }
hectare^{ }

min
h
d
°
'
"
L*^{ }
t^{ }
ha^{ }

1 min = 60 s
1 h = 60 min = 3600 s
1 d = 24h = 86,400 s
l = (p/I 80) rad
1' = (1/60)° = (p 10800) rad
1" = (1/60)' = (p/648 000) rad
1 L = 11 dml = 10^{3} M^{3}
1 t = 10^{3} kg
1 ha = 10^{4} M^{2}

*The international symbol for liter is the lowercase 'l', which can be confused with the number "1." Therefore the symbol "L' or spelling out the term liter is advisable.
Prefixes
The sixteen prefixes in Table 26 are used to form multiples and submultiples of the SI units. The use of more than one prefix is to be avoided (e.g. pico instead of micromicro and giga instead of kilomega). The preferred pronunciation of the terms is also included in the table. The accent is on the first syllable of each prefix.
Table 26. Metric Prefixes 
Muftiplication Factor  Prefix  Abbreviation  Pronunciation 
10^{18}
10^{15}
10^{12}
10^{9}
10^{6}
10^{3}
10^{2}
10 ^{ }
10^{1}
10^{2}
10^{1}
10^{6}
10^{9}
10^{12}
10^{15}
10^{16}

exa
peta^{ }
tera^{ }
giga^{ }
mega^{ }
kilo^{ }
hecto^{ }
deka^{ }
deci^{ }
centi^{ }
milli^{}
micro^{ }
nano^{ }
pico^{ }
fernto^{ }
atto^{ }

E P^{ } T^{ } G M^{ } k^{ } h*^{ } da*^{ } d*^{ } C*^{ } m^{ } µ^{ } n^{ } p^{ } f^{ } a^{ }

ex'a (a as in a bout)
as in petal^{ }
as in terrace^{ }
jig'a (a as in a bout)^{ }
as in mega phone^{ }
as in kilowatt^{ }
heck' toe^{ }
deck'a (a as in a bout)^{ }
as in decimal^{ }
as in sentiment^{ }
as in military^{ }
as in microphone^{ }
nan'oh (an as in ant)^{ }
peek'oh^{ }
fern'toe (fem as in feminine)^{ }
as in anatomy^{ }

.The use 0f hecto, deka, deci, and centi should be avoided for SI unit multiples except for area and volume, and the nontechnical use of centimeter for body and clothing measurements.
Updated February 1999
