375 TABLES 370-406.-VAKIOUS ELECTRICAL CHARACTERISTICS OF MATERIALS
The fundamental electrical and magnetic definitions and the values of the practical units of current, voltage, and other electrical quantities, have been given (Tables 2-5). Some data will now be presented on electrical characteristics of various materials.
T A B L E 370.-THE EFFECT O F ELECTRIC CURRENT ON T H E H U M A N BODY'@*
Some thought must be given to the electrical characteristics of the human body, since careless handling of electric circuits is very dangerous. The regular 120-volt circuit is dangerous, and any voltage above this increases the hazard. No bare contacts should be permitted where anyone might come in contact with them.
A C (60cycles) DC Threshold of perception ....................................... 1 ma ...... 5 ma muscular decontrol .............................. 15 ......
6o
1;}-24.5
: - 11 '}3 .
':}-46.0
:}-33.4
Bismuth sulfide 1
'>
68.1
T A B L E 377.-THERMOELECTRIC
EFFECT
A measure of the thermoelectric effect of a circuit of two metals is the electromotive force produced by 1"C difference of tempcrature between the junctions. The thermoelectric Bt, effect varies with the temperature, thus. thermoelectric effect = Q = d E / d t = A where A is the thermoelectric effect at O"C, B is a constant, and t is the mean temperature of the junctions. The neutral point is the temperature at which d E / d t = 0, and its value is - A / B . When a current is caused to flow in a circuit of two metals originally a t a uniform temperature, heat is liberated at one of the junctions and absorbed at the other. The rate of production or liberation of hcat at each junction. or Peltier effect, is given in calories per second, by multiplying the current by the coefficient of the Peltier effect. This coefficient in calories per coulomb = QT/T, in which Q is in volts per degree C, T is the absolute temperature of the junction, and 7 = 4.19. Heat is also liberated or absorbed in each of the metals as the current flows through portions of varying temperature. The rate of production or liberation of heat in each metal, or the Thomson effect, is given in calories per second by multiplying the current by the coefficient of the Thomson effect. This coefficient, in calories per coulomb = BTsIT, in which B is in volts per degree C, T is the mean absolute temperature of the junctions. and 0 is the difference of temperature of the junctions. ( B T ) is Sir W . Thomson's "Specific Heat of Electricity," The algebraic signs are so chosen in the following table that when A is positive, the current flows in the metal considered from the hot junction to the cold. When B is positive, Q increases (algebraically) with the temperature. The values of A , B , and thermoelectric effect in the following table are with rcsprct to lcad as the other metal of the thermoelectric circuit. The thermoelectric effect of a couple composed of two metals, 1 and 2, is given by subtracting the value for 2 from that for 1 ; when this difference is positive, the current flows from the hot junction to the cold in 1. In the following table, A is given in microvolts per degree, B in microvolts per degree per degree, and the neutral point in degrees. The table has been compiled from the results of Becquerel, Matthiessen and Tait; in reducing the results, the electromotive force of the Grove and Daniel1 cells has been taken as 1.95 and 1.07 volts. The value of constantan was reduced from results given in LandoltBornstein's tables. (coiitinued)
+
SMITHSONIAN PHYSICAL TABLES
380
TABLE 377.-THERMOELECTRIC
EFFECT (concluded)
A
B
Microvolts
Thermoelectric effect at mean temp. of junctions (microvolts)
Aluminum ..................... - .76 Antimony, comm'l pressed wire.. axial ................ equatorial ............ A r g y t a n ...................... -1 1.94
Substance
Microvolts
+.0039
-
20°C
Neutral point
Arsenic ....................... Bismuth, comm'l pressed wire.. . ' pure ... ' crystal, axial ......... " equatorial ..... Cadmium ...................... 2.63 fused ................ Calcium ....................... Cobalt ........................ Constantan .................... C o q p r ........................ 1.34 commercial ............ ' galvanoplastic .......... Gallium ....................... Gold .......................... 2.80 Iron .......................... +17.15 '' pianoforte wire ............ " commercial ............... ............... Lead .......................... Magnesium .................... 2.22 Molybdenum ................... Mercury ...................... Nickel ........................ " (-18" t o 175") ........... -21.8 " (250"-300") ............. -83.57 " (above 340") ............. - 3.04 Palladium ..................... - 6.18 Phosphorus (red) .............. Platinum ...................... " (hardened) ........... 2.57 '' (malleable) ........... - .60 wire ................. ' another specimen ...... Platinum-iridium alloys : 85% P t 15% I r ........... 7.90 90% P t 10% Ir ........... 5.90 5% I r ........... 6.15 95% P t Selenium ....................... Silver ......................... 2.12 " (pure hard) .............. " wire .................... Steel .......................... +11.27 Tantalum ...................... T e l l y i u m * p .................. -
......................
-
-.0506
-
+
+
13.56 - 97.0 - 89.0 - 65.0 - 45.0 3.48 -
+ 22.6 6.0 + + 26.4 - 12.95
-
.68
-
50°C
.56 -14.47 -12.7 -
+ 195 - 236
A -B
-
-
+
- 22
+
+.0101 -.0482
-
+ 1.52 + .10 + 3.8 - .2 + 3.0 + 16.2 + 17.5 -
-
+ 4.75 + 2.45 + 8.9 -19.3 1.81 3.30 +14.74 +12.10 9.10
-
62
+
- 143
+
[-
+ 356
2771
--.0094 -
+
.oooo
+
-.0506 +.2384 -.0506 -.0355 -.0074 -.0109
+ + + + + +
2.03 5.9 .413 -
.oo
+ .oo + 1.75
- 3.30 -15.50 -24.33
-
+ 236 [-
-
- 22.8 - 6.9 29.9
2.42 - .818 -
-
.F
-
- 7.96 2.20 - 1.15 .94 - 2.14
4311 174
+ +
347 - 55 -12741 444 -11181 - 144
+ + +
+ + +
-.0325 +.0147
+.0062 -.0133 .0055
+
........................... ........................... Tungsten ...................... Zinc ..........................
I'
Thallium ...................... Tin (commercial) ..............
a
..................
.
pure pressed.. .............
- .43 2.32
-
- 2.6 +500. +160.
+ 8.03 + 5.63 + 6.26 +807. + 2.41 + 3.00 + 10.62
. 8
+ 8.21 + 5.23 + 6.42 + 2.86 + 2.18
-
+
-
+.0055 f.0238 -
-
+
-
+ +
-
+
.33 2.0 2.79 3.7
.I
.33 - .16 3.51 -
+ 9.65 -
347 -
+
+
Electrical conductivity of Tea = 0.04, Tea = 1.7 emu.
SMITHSONIAN PHYSICAL TABLES
38 1
T A B L E 378.-THERMAL E L E C T R O M O T I V E FORCE O F M E T A L S A N D A L L O Y S VERSUS P L A T I N U M
(millivolts) indicates that the current flows from the 0" One junction is supposed to be at 0°C; junction into the platinum. The rhodium and iridium were rolled, the other metals drawn.
Temperature, "C
Au
+
-185 - 80 +loo +200 +300 +400 +SO0 +600 +700
+800
+900 +lo00 +1100 +(1300) +(1500)
- .15 - .16 - .31 - .30 .74 .72 +1.7 +1.8 +3.0 +3.0 +4.5 +4.5 +6.2 +6.1 +8.2 +7.9 +9.9 +10.6 +12.0 +13.2 +14.3 +16.0 -+16.8 --
Ag
90%Pt+ 100,hPd
- .ll
+
+
- .09
+ .26
.62 +1.0 +1.5 +1.9 +2.4 +2.9 +3.4 +3.8 +4.3 +4.8
+
+ .24 + .77 + .15 + .39 - .19 - .56
- .31 - .37 - .35
1WOPt+ 90"/uPd
Pd
90%Pt+ 90070 P t f 10C/ORu 10%Rh
- .18
+1.2 +2.1 +3.1 +4.2
+ .12 + .61
--
-
- - -
-1.20 -2.0 -2.8 -3.8 -4.9 -6.3 -7.9 -9.6 -11.5 -13.5
- - .53 - .28 - .24 - - .39 - .32 - .31 -+ .73 + .65 + .65 - +1.6 +1.5 +1.5
+2.6 +3.6 +4.6 +5.7 +6.9
+8.0
Ir
Rh
--
-
+2.3 +3.2 +4.1 +5.1 +6.2 +7.2 +8.3 +9.5 +10.6 +13.1 +15.6
+9.2 +10.4 +11.6 +14.2 +16.9
+2.5 +3.6 +4.8 +6.1 +7.6 -9.1 f10.8 +12.6 +14.5 +18.6 +23.1
+2.6 +3.7 +5.1 +6.5 +8.1 +9.9 +11.7 +13.7 +15.8 +20.4 +25.6
T A B L E 379.-THERMOELECTRIC
PROPERTIES A T L O W TEMPERATURES"'
Thermoelectric emf per "K against silver alloy
"C
cu
Ag
Au
-255 -240 -220 -200 -180 -160 -140 -120 -100 - 80 - 60 - 40 - 20 0 20
+.07 .45 .90
-.lo +.37 .39
.44
.20
-1.20 - .05 .24 .30 .30 .33 .3f .40 .44
+
47 . ..
.51
.55
.58
.53 .56 .21 .22
+
.62 .65
2.10 3.40 3.48 2.14 .54 -1.06 -2.52 -3.92 -5.27 -6.52 -7.80 -9.05 -10.32 -11.6
+ .75
Pd
Pt
Fe
Pb
+1.54 3.60 5.24 5.40 4.36 3.02 1.72 -1.76 -2.80 -3.80 -4.72 -5.62 -6.56
- .70
.so
+.05 1.40 4.80 8.45 11.5 14.0 15.8 16.9 17.5 17.5 17.3 16.9 16.2 15.8 15.3
-1.06 -1.19 -1.25 -1.29 -1.33 -1.42 -1.54 -1.67 -1.79 -1.92 -2.05 -2.17 -2.29 -2.42 -2.54
11 '
Borelius, Keesom, Johansson, Linde, Com. Phys. Lab. Leiden, No. 206, 1930.
T A B L E 380.-PELTIER
Temperature
00
E F F E C T , FE-CONSTANTAN, NI-CU, 0" -560°C
20'
130"
240'
Fe-Constantan
NiCu
. . . . . . . . 3.1 ............ .... 1.92
320"
560°C
3.6 2.15
4.5 2.45
6.2
8.2 1.91
12.5 2.38
2.06
SMITHWNIAN PHYSICAL TABLES
382
"K
T A B L E 381.-THOMSON
cu
E F F E C T IiN MICROVOLTS P E R DEGREE
Pa Pt Fe Ni co
AK
Au
20 25 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 200 220 240 260 280 300
4-.59
1.04 1.22 1.03 .67 .18 - .29 - .46 - .48 - .45 - .37 - .26 - .13 .02 .17 .31 .46 .59 .79 .96 1.10 1.24 1.38 +1.52
+
$1.40 1.23 .85 .24 - .02 - .17 - .24 - .25 - .17 - .03 .12 .25 .35 .44 .52
+2.S3 2.09 1.58 .88 .45 .19 .07
+
.17 .32 .45 .56 .75 .83 .9 1 .99 1.06 1.19 1.31 1.43 1.54 1.66 +1.77
.05
.66
.59
.66 .72 .84 .96 1.08 1.20 1.32 +1.44
+1.9 2.6 3.1 3.2 2.5 1.0 -1.5 -4.6 -6.6 -7.8 -8.7 -9.3 -9.7 -10.1 -10.3 -10.6 -10.9 -11.2 -12.1 -13.3 -14 6 -15.8 -17.0 -18.2
f3.2 3.6 3.9 3.8 2.7 1.o -1.1 -3.3 -5.1 -6.5 -7.5 -8.0 -8.2 -8.2 -8.3 -8.4 -8.5 -8.7 -9.1 -9.8 -10.6 -11.4 -12.3 -13.2
$1.3 2.7 4.1 6.7 9.0 10.8 11.9 12.6 12.9 13.0 13.0 12.8 12.2 11.0 8.9 6.1 2.6 - .2 -3.5 -4.5 -4.8 -5.2 -5 6 -5.9
-4 5 -5.4 -5.0 -4.5 -4.1 -4.0 -4.0 -4.5 -5.3 -6.4 -7.4 -8.3 -9.0 -9.7 -10.3 -10.9 -12.1 -13.3 -14.5 -15.7
... ...
...
...
- .2 - .3 - .8 -2.0 -3.7 -5.5 -7.0 -8.4 -9.8 -11.1 -12.4 -13.5 -14.6 -15.7 -16.7 -17.6 -19.6 -21.5 -23.4 -25.4
...
...
... ...
-.04 -.06 -.09 -.12 -.15 -.18 -20 -.23 -26 -29 -.32 -.34 -.37 -.40 -.42 -.46 -.49 -9 -274
... ... .00
Pb
-55
-.57
T A B L E 382.-T
H E RM 0 E L E C T R I C E F F E C T S ; P R ESSU R E E F F E C T S
The following values of the thermoelectric effects under various pressures are taken from Bridgman. A positive emf means that the current at the hot junction flows from the uncompressed to the compressed metal. The cold junction is always at 0°C. The last two columns give the constants in the equation E =thermoelectric force aqainst lead (0" to 100°C) = ( A t Bt') X lo-" volts; a t atmospheric pressure, a positive emf meaning that the current flows from lead to the metal under consideration at the hot junction.
+
Thermal emf, volts X lo9 Pressure, kg/cm*
2000 4000 8000 12,000
Temperature,
I
"C
50" 1000 20" 185,000 452,000 710,000 14,400 38,500 87,400 8,780 23,750 52,460 6,680 19,180 45,560 6,750 17,200 35,470 5,090 12,970 26,520 3,880 11,030 21,570 7,050 15,140 2,700 5,140 11,440 1,880 4,950 10,560 +1,900 7,680 220 -990 281 6,330 +880 5.760 2,627 +990 1,616 3,546 +596 1,962 312 -68 833 5 62 +146 +390 -182 +lo -719 -1,314 -308 -648 -1,296 -259 -352 -937 -2,061
Formula coefficients
Metal Bi .......... Zn . . . . . .
50"
100'
50'
.... T .......... I Cd . . . . . . . . . . Constantan . . Pd . . . . . . . . . . Pt . . . . . . . . . . w .. . . . . . . .,
Ni Ag Fe Pb Au
..__...... . . . . .. . . . .......... . . . . . . .... . . . ... . . . cu .. . . .. . ,. A1 . . . . . . . . . . Mo . . . . . . . . . Sn . . . . . . . . . .
Manganin MK ......... c o . ..
100" 185,000 28500 20:290 14,380 11,810 8,800 7,310 4,990 3,400 3,720 3,250 2,120 2,051 1,216 294 278 -452 -362 --692
... . ......
+ins
50" 255,000 26100 17:170 10,960 11,530 8,630 7,370 4,690 3,230 3,350 5,300 1,860 1,791 1,124 32 375 +70 -489 --395 -630
1000
425,000 58,100 37,630 28,740 23,790 17,690 14,350 10.120 7,190 7,190 5,820 4,210 3,974 2,420 929 555 +292 -894 -791 -1,360
' A -74.42 +3.047 +1.659 +12.002 -34.76 -5.496 -3.092 +1.594 -17.61 +2.556 +16.18
B
f.0160 --.00495 -.OO 134' +.1619 --.0397 -.01760 -.01334 f.01705 -.0178 +.00432b -.0089b
-
-
+2.899 +2.777 -.416 +5.892 +.230 +1.366 -.095 -17.32
+.00467e f.00483
+.00008d +.02 1670 --.00067 +.000414f +.00004 -.0390
a, --.0s56ta; b, -.0d36ta,
annealed ingot iron; c, -.0a166ta;
d. -.0,1t8;
e. -.0,25ts;
f , -.04112t8
SMITHSONIAN PHYSICAL TABLES
T A B L E 383.-PELTIER
A N D T H O M S O N H E A T S ; PRESSURE E F F E C T S
383
The following data indicate the magnitude of the effect of pressure on the Peltier and Thomson heats. They refer to the same samples as for the last table. The Peltier heat is considered positive if heat is absorbed by the positive current from the surroundings on flowing from uncompressed to compressed metal. A positive dZE/dtzmeans a larger Thomson heat in the compressed metal, and the Thomson heat is itself considered positive if heat is absorbed by the positive current in flowing from cold to hot metal. Same reference as footnote 141, and notes as for preceding table.
1W x Joules/coulomb
Pressure kg/cmP Peltier heat, Thomson heat 108 X J X coulomb-; 'C-1 Pressure kg/cm*
6000
I
12,000
Temperature "C
6000
12,000
Temperature "C
00 50' 1000 0' 50" Metal Bi - +25W +2810 +lo70 +I210 Zn 4-140 3.190 +98 +190 +278 TI +95 +124 +I12 4-17] +66 Cd +71 4-118 +81 4-148 +19 Constantan 4-46 4-57 +70 4-90 f114 Pd .......... +35 4-43 +52 +68 +86 Pt +45 +76 +23 +37 4-35 w .......... 4-17 4-25 +32 +36 +49 Ni .......... 3-11 4-17 +23 +24 +37 Ag +34 Fe -38 +38 Pb .......... 4-10 +16 4-14 +20 A u ......... 4-10 +14 +13 +18 c u ......... 4-4 +6 A1 .......... Mo Sn Manganin ... -2 -2 -2 -4 -4 Mg -16 -a1 -35 -42 -18 co -23 -33 -44 -46 -67
1000
.......... .......... .......... .......... .. ..........
......... ..........
-
0"
+llSO +lo9
+S
50" +650
+48
100'
$412 4-229 4-221 +I40 +lo3 4-65
+6S
$ : !
+44 +36
+25
+so
+la
' -$ +-'6 -% '+"+ 9" +8 4-7 +6 +9 4-7 +8
+4 +79
+2
+28 +74 +6
+56 +26
+63 +6
+30
+4
+SS +6 +4
4-0
+5
+6 -121
$10
+5
50" 10 0' -405 +133 +220 +63 +SO +lo5 +92 4-93 f13 +14 4-17 +9 +8 +17 +59 +14 +20 +15 4-10 +16 +lo 4-7 +8 -347 +lZO -194 +20 +6 +8 +6 4-7 +6
0'
-520 +63 +79
......... .......... ......... ..........
2: +2
-4
+2
4 8
+6 +; +A -14
-11
-1 +o"
+29
+o"
-11 +2
-2
-5
+A +;
-28
-90
-10
-20
-24
T A B L E 384.-THERMAL
E L E C T R O M O T I V E FORCE O F C A D M I U M VERSUS P L A T 1NUM
Temperature versus emf
"C
0 25 50 75 100
+.171 .378 620 .898
.ooo
mv
"C
mv
"C
mv
125 150 175 200 225
1.211 1.559 1.940 2.351 2.790
250 275 300 315
3.255 3.740 4.238 4.539
T A B L E 385.-PELTIER
EFFECT
The coefficient of Peltier effect mav be calculated from the constants A and R of Table 377, as there shown. With Q (see Table 377) in microvolts per "C and T = absolute temperature ( K ) , the coefficient of Peltier effect = - cal per coulomb =O.O0086 QT cal QT 42 per ampere-hour = QT/1000 millivolts (= millijoules per coulomb). Experimental results, expressed in slightly different units are here given. The figures are for the heat production at a junction of copper and the metal named in calories per ampere-hour. The current flowing from copper to the metal named, a positive sign indicates a warming of the junction.
Calories per ampere-hour Sb.
-
Sb commercial t Bi pure
-
-
Bit
-
Cd
German silver
-.62 .46
-
Fe
Ni
Pt
Ag
Zn
-3.61 2.5
4.36
.32
-.41
-.58
.39
13.02
$8
19.1
25.8
2.47
-
-
-
*Becquerel's antimony is 806 parts Sb+406 arts Z n + 121 parts Bi. t Becquerel's bismuth i s 10 parts Bi 1 part gb.
+
SMITHSONIAN PHYSICAL TABLES
384
TABLE 386.-RESISTIVITY
OF METALS AND SOME ALLOYS
The resistivities are the values of p in the equation R = pl/s, where R is the resistance in microhms of a length I cm of uniform cross section s cmz. The temperature coefficient is a, in the formula Rt = R.[1 a,(t - t , ) ] . The information of column 2 does not necessarily apply to the temperature coefficient.
+
Tempera-
Temperature coefficient
Advance ........... see constantan Aluminum ......... -......... c.p.
Substance
Remarks
tpe
C
Microhmcm
-18" 25 100 500
t*
__
+.0039 +.0034 +.0040 +.0050 +.0036 -
a,
'
.........
20 -189
-100
'
......... AntiFony .......... -_ __ .......... .......... liquid Arsenic ............ __ Beryllium ......... __ Bisrffuth . . . . . . . . . . . __ __ ........... Brass ............. __ Cadmium .......... drawn .......... .......... .......... liquid Calcium ........... 99.57 pure Calido ............. see nichrome Cesium ............ -__ ............ ' ............ ' ............ liquid } solid Chromium ......... __ Climax ............ __
" "
.........
0 $100 400
-190
n
+860 0 20 18 100 20 -160 18 100 318 20
2.828 .64 1.53 2.62 3.86 8.0 39.1 10.5 120 35 10.1 119.0 160.2
7
__ __
__ -_ +.004 __
20 20 +.W2 +.0038 +.0036
-
_-
-187
0 27 30 0 20 20 20 --
__ ........ __ ........ __ ........ __ ........ C o y e r ............ annealed ............ hard-drawn ' ............ electrolytic ............ . . . . . . . . . . . . . pure . . . . . . . . . . . . . very pure, ann'ld Eureka ............ see constantan _Excello ............ Gallium ........... __ German silver ...... 18% Ni Germanium ........ __ Gold .............. 99.9 pure __ .............. .............. pure, drawn . . . . . . . . . . . . . . . . 99.9 pure Ia Ia .............. see constantan Ideal ................ Indium ............ Iridium ............ __ ............ __ ............ Iron ............... 99.98% pure ' ............... pure, soft ............... ...............
" " " " " " "
Cobalt ............. 99.8 pure Comfantan ........ 60% Cu. 40% Ni
2.72 7.54 9.82 34.1 4.59 5.25 19 22.2 36.6 13 87 9.7 49
__ -__ __
20 12 25
+.0007
__ __
20 20 -206 +205 400 20 20 0 20
0
-183
0 20 194.5 0
1.724 1.77 .I44 2.92 4.10 1.692 92 53 33 89000. .68 2.22 2.44 3.77
2
"
1000
100 400
20
-
-.000033 -.000020 +.WOO27 +.00393 +.00382 +.0038 .0042 +.0062 -
+.000002
+.oooOO8
+
-
20
"
+.00016 +.0004 -
500 1000
20 100 an;'ld
-186
-205.3 - 78
0
+l2
0
8.37 1.92 6.10 8.3
10
__ __
20 25 100
0
,652 5.32 8.85
+.0050 +.OM2 +.0052 +.0068
lntinued)
SMITHWNIAN PHYSICAL TABLES
T A B L E 386.-RESISTIV
I T Y O F M ETALLS AND SOME ALLOYS (continued)
Temperatye
385
Substance
1r:n
............... pure,
............
'I
Remarks
soft
" "
Le;d
_........... ... ........... ... cs!d pre:sed ' ........... ... ........... ........... ... __ ........... ... solid Lithium ........ ' ........ ... ........ ... ........ ... liquid __ Magnesium ..... ... ' ..... ... free from '
1'
............ ... ............ ............
"
electrolytic
"
..... ... ........
..... ...
" "
" "
I.'
"
"
I'
91.30 53.85 36.70 25.00 16.53 8.89 4.06
"
"
"
............
NoTE.-Barus has pointed out that the temperature variation of platinum alloys containing less than 10% of the other metal can be nearly expressed by an equation y =? -fi:,
z
where y is the temperature coefficient and x the specific resistance, m and n being constants. If a be the temperature coefficient at 0°C and s the corresponding specific resistance, s(a m ) =n For platinum alloys Barus's experiments gave nt = -.000194 and n = .0378. For steel in = -.U00303 and n = ,0620. Matthiessen's experiments reduced by Barus gave for Gold alloys m = -.000045, n = .00721. Silver m = -.000112, n = .00538. Copper m = -.000386, n = .00055.
+
::
(cn?tt;?tlled)
SMITHSONIAN PHYSICAL TABLES
392
TABLE 397.-ELECTRICAL CONDUCTIVITY O F ALLOYS (concluded)
Part 3
L
Weight "/o
Volume 7%
Alloys
of first named
c .. o
Gold-copper Gold-silver
'I I'
"
'I
'1
"
'I
I'
'I
"
........... ............ 87.95 ............ 87.95 ............ 64.80 ............ 64.80 ............ 31.33 ............ 31.33
...........
34.83
...........
104
a X 108
b X lon
99.23 90.55
98.36 81.66 79.86 79.86 52.08 52.08 19.86 19.86 19.17 .71 19.65 5.05 2.51 23.28 98.35 95.17 77.64 46.67 8.25 1.53 27.93 21.18 10.96
35.42 10.16 13.46 13.61 9.48 9.51 13.69 13.73 12.94 53.02 4.22 11.38 19.96 5.38 56.49 51.93 44.06 47.29 50.65 50.30 1.73 1.26 1.46 24.51 4.62 14.91 3.97 8.12 38.52
2650 749 1090 1140 673 721 885 908
4650 81 793 1160 246 495 531 641 570 7300 208 656 1150 154 7990 6940 6070 5280 4360 8740 7010 1220 103
GEld-coqper
............ 1.52 Platiym-silver ........ 33.33 ' ........ 9.81
'
864
3320 330 774 1240 324 3450 3250 3030 2870 2750 4120 3490 2970 487 1550 476 1320 516 736 2640
........
5.00
Palladium-silver Copper-silver
" " " "
.......... 94.40 .......... 76.74 .......... 42.75 .......... 7.14 .......... 1.31
13.59 9.80 4.76
....... ..........
25.00 98.08
Iron-gold
" " " "
Iron-copper
"
.............. . . . . . . . . . . . . .40 Phosphorus-copper ..... 2.50
" "
.............. ..............
. . . . . .95
5.40 2.80 trace
.46 . .
.
2090
145 1640 989 446 4830
Arsenic-copper
'
......... .........
.........
-
SMITHSONIAN PHYSICAL TABLES
T A B L E 398.-RESISTIVITIES
A T HIGH AND L O W T E M P E R A T U R E S
393
The electrical resistivity ( p , ohm-cm) of good conductors depends greatly on chemical purity, Slight contamination even with metals of lower p may greatly increase p . Solid solutions of good conductors generally have higher p than components. Reverse is true of bad conductors. I n solid state allotropic and crystalline forms greatly modify p . For liquid metals this last cause of variability disappears. The temperature coefficients of pure metals is of the same order as the coefficients of expansion of gases. For temperature resistance ( t , p ) plot at low temperatures the graph is convex toward the axis of t and probably approaches tangency to it. However for extremely low temperatures Onnes finds very sudden and great drops in p, e.g., for mercury, PJ.~K 200,000,000.
2oo.ono. 30.000. m.
30. about 20.
900. 1000. 1100. 1200. 1600.
>9X10a 30800. 13600. 7600. 6500. 2300. 190.
Diamond 1030"C, p
> 107; 1380",
7.5 X 105.
T A B L E 399.-SUPERCONDUCTIVITY
Metal T"K Metal
O F SOME M E T A L S
T"K
Metal
............... .... .... Ta . . . . . . . . . . . . . . .
Nh
9.22 7.2 5.2 4.4 . . . . 4.3 Hg . . . . . . . . . . . . . . 4.15 Sn . . . . . . . . . . . . . . . 3.71
I n . . . . . . . . . . . . . . . 3.38
u ...............
0s
T"K
Zr . . . . . . . . . . . . . . .
Al . . . . . . . . . . . . . . . 1.15
. . . . . . . . . . . . . . . .71
.75
.54*
Zn
. . . . . . . . . . . . . . .95t
Ti . . . . . . . . . . . . . . . .53t Ru . . . . . . . . . . . . . . . .47 Hf . . . . . . . . . . . . . . . .35
s ' Smith Thomas S., Ohio State University, private communication. 1 D a u n t . ' J . G., and Smith. T . S. t Daunt, J . G., and Heer. C. V.. Phys. Rev., vol. 76, pp. 719 and 1324, 1948.
T A B L E 400.-SUPERCONDUCTIVITY
OF SOME ALLOYS A N D COMPOUNDS"e
NhC . . . . . . . TaC ....... Ph-As-Bi .. Ph-Ri-Sh .. P b S n - B i ..
14"
10.1"K 9.2 9.0 8.9 8.5
Ph-As alloy. MoC . . . . . . . NiPh ..... BioTI, . . . . . . ShzTIT . . . . . TaSi .......
8.4"K 7.7 7.2 6.5
5.5
PhS ....... Hg5T17. . . . . ZrR . . . . . . . WC . . . . . . . MozC . . . . . .
4.1"K 3.8 2.82 2.8 2.4
4.2
W,C . . . . . . . AulBi . . . . . . CuS ....... T i N ....... V N ........ T i c ........
2.05"K 1.84 1.6 1.4 1.3 1.1
Smith, G . I f . . an(l LVilhelm. J. 0.. Rev. hlod. Phys., vol. 7 , p. 240, 1935
SMITHSONIAN PHYSICAL TABLES
395
T A B L E 401.-VOLUME A N D SURFACE RESISTANCE
OF SOLID DIELECTRICS
The resistance between two conductors insulated by a solid dielectric depends both upon the surface resistance and the volume resistance of the insulator. T h e volume resistivity, p, is the resistance betweeii two opposite faces of a centimeter cube. The surface resistivity, u, is the resistance between two opposite edges of a centimeter square of the surface. The surface resistivity usually varies through a wide range with the humidity.
Material
u ; megohms 50% humidity
u ; megohms 70% humidity
Amber . ....... ... . ...... .... . .... Beeswax, yellow . . . . . . . . . . . . . . . . . . Celluloid . . . . . . . . . . . . . . . . . . . . . . . . . Fiber. red ........................
u : megohms 9 0 1 humidity
P
Megohm-cm
6x10' 6x10" 5X 10: 2x10
Sulfur . . . . . . . . . . Wood, paraffined mahogany
. . . . . . . . 4x10'
2 x 10' 6x10' 2x104 3X103 6% 10 4X103 1x10' 11 3 x0 3>lo" PbOz, synthetic . . . . . . . . . . .OOOO92 MnOl, synthetic .... ...... 6 W20s . . . . . . . . . . . . . . . . . . . ,00045 wo, . . . . . . . . . . . . . . . . . . . 2x106
Material
Resistivity ohm-cm
T A B L E 403.-ELECTRICAL
RESISTIVITY O F ROCKS A N D SOILS *
Sedimentary rocks Resistivity ohm-cm
Granite . . . . . . . . . . . . . . . . . . . . Lava flow (basic) . . . . . . . . . . . Lava, fresh . .... . ... . ..... .. Quartz vein, massive . . . . . . .
Igneous rocks
Resistivity ohm-cm
.
107-1 0 9 108-10' 0 3 x 106-1'
>I00
Resistivity ohm-cm
Limestone . . . . . . . . . . . . . . . . . . Limestone, Cambrian . . . . . . . Sandstone, eastern . . . . . . . . . . Sandstone . . . . . . . . . . . . . . . . . . Limestone . . . . . . . . . . . . . . . . .
.
10' 104-106 ' 3 X 10x-10 1O6
106
Resistivity ohm-cm
Marble, white ... ........... Marble . . . . . . . . . . . . . . . . . . .. Marble, yellow . . . . . . . . . . . . . Schist, mica . ... ... ... . . ... . Shale, Nonesuch . . . . . . . . . . . Shale, bed .............. ...
Metamorphic rocks
1O'O 4x10'
.
loio 107
104 106
Clay, blue . ... ... .......... Clayey earth . .............. Clay, fire ... . .... .... ... . .. Gravel . , . . . . .. . . .. . , ,. , . .. Sand, dry . ... .... ... ....... Sand, moist ... .............
Unconsolidated materials
2x105
2x10' 10'-4X 10' 1O6 1O6-l0' 105-100
*For reference, see footnote 4 5 , p. 136.
SMITHSONIAN PHYSICAL TABLES
396
T A B L E 404.-RESISTIVITY OF SOILS A N D SEA W A T E R M E A S U R E D W I T H HIGH-FREQUENCY ALTERNATING CURRENT
*
Soil, very dry .. 1 to 10,000 Topsoil, dry .... 37,000
Material
Frequency Resistivity kilocvcles/sec ohm/cm
Material
Frequency Resistivity kilocycles/sec ohm/cm
10' 7,000
Clay, dry ....... Chalk (moisture, 24%) Sea water
37,000 100 1.200 10:660 100 1,200 10,000
60,000 33,000 22.000 141000 21 21 16.5
Loam, dark (moisture, 60%)
100 1,200 10,Ooo
2,600 2,300 1,500
For reference, see footnote 45, p. 136.
T A B L E 405.-ELECTRICAL
Material
RESISTIVITY OF NATURAL WATERS
Resistivity ohm-cm Material
*
Resistivity ohm-cm
Very fresh distilled waters ...... 2x10' Mine waters ................... 500
For reference. see footnote 15, p. 136.
Potable ground waters ......... 108-106 Surface waters ................ 10'
T A B L E 406.-RESISTIVITY OF S O M E GLASSES A T T H R E E TEM PE RATURES
Log 10
Volume resistivity (ohm-cm)
/ -
Potash soda lead ...... Lamp tubing Soda lime ............ Lamp bulbs Potash soda lead ...... Lamp tubing H a r d Lime ........... Cooking utensils Borosilicate ........... Kovar sealing Borosilicate ........... Low loss electrical Borosilicate ........... Baking ware Pyrex ................ General Vycor ................ Low expansion ultraviolet transmission Fused quartz ..........
Glass
Principal use
Density
25°C
250°C
350°C
2.85 2.47 3.05 2.53 2.28 2.13 2.24 2.23 2.18 2.20
17.+ 12.4 17.+ 17.+ 17. 17.+ 15. 15. 17.+
8.9 6.4 10.1 11.4 9.2 11.2 8.2 8.1 11.2
7.0 5.1 8.0 9.4 7.4 9.1 6.7 6.6 9.2 10.48
1 Corning Glass Co. publication, Properties of selected commercial glasses, 1949. General Electric " Co. publication, Fused quartz, 1947.
SMITHSONIAN PHYSICAL TABLES