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Luminous efficiencies of various sources of light (lumens per watt). For spectral energy distribution data see references 28, 29a, 29b and 41. Methods of measurement and data are discussed comprehensively in reference 37.
Value given by L. J. Buttolph, reference 41.
A. C. Downes, Elect. Eng. 54, 761 (1935), states that efficiencies as high as 79 L/W have been obtained.
Based on Vλ for D lines.
Value calculated by F. A. Benford from energy distribution.
Calculated from energy-distribution data obtained in this laboratory by G. R. Fonda.
Values obtained by G. E. Inman, Incandescent Lamp Division, General Electric Co., Cleveland, Ohio.
Table II
Total energy and luminous characteristics of a black-body radiator.
T Deg. K
W Watts Per cm2
L Lumens Per cm2
Ls Lumens Per watt
L0 Lumens Per watt
η
2000
91.4
1.40×102
1.53
153
0.01
3000
426.4
8.89×103
19.2
206.7
0.093
4000
1462
7.32×104
50.1
219.6
0.228
5000
3570
2.64×105
73.9
229.3
0.322
5500
5226
4.22×105
82.6
227.9
0.362
6000
7403
6.22×105
84.0
221.1
0.380
6500
10190
8.75×105
86.3
218.5
0.395
7000
13710
11.53×105
84.1
212.9
0.395
Table III
Critical Potentials, Resonance Lines, and Metastable Levels
Atom
Vr
λr
Vm
Vi
Lithium (Li)
1.84
6,708
5.37
Sodium (Na)
2.10
5,890; 5,896
5.12
Potassium (K)
1.60
7,645; 7,699
4.32
Rubidium (Rb)
1.56
7,800; 7,948
4.16
Caesium (Cs)
1.38; 1.45
8,521; 8,943
3.87
Helium (He)
20.91
592
19.77
24.47
21.12
584
20.55
Neon (Ne)
16.58
744
16.53
21.47
16.77
736
16.62
Argon (A)
11.56
1,067
11.49
15.69
11.77
1,048
11.66
Krypton (Kr)
9.98
1,236
9.86
13.94
10.59
1,165
10.51
Xenon (Xe)
8.39
1,469
8.28
12.08
9.52
1,295
9.40
Zinc (Zn)
4.01
3,076
3.99
9.36
5.77
2,139
4.06
Cadmium (Cd)
3.78
3,261
3.71
8.96
5.39
2,288
3.93
Mercury (Hg)
4.87
2,537
4.64
10.38
6.67
1,850
5.44
Thallium (Tl)
3.27
3,776
0.96
6.07
4.46
2,768
Table IV
Data for positive column discharge in sodium and sodium plus neon tube diameter=3.6 cm.
ER
EW
t°C
p(Na) mm
p(Ne) mm
Arc amp.
Gvolts/cm
Te
ne·10−10
Percentage of Total
255
0.0021
0
0.2
0.432
30,950
1.01
92.2
13.3
0
1.0
0.398
19,200
4.55
93.7
13.8
1.0
0.504
9,100
39.9
88.8
12.5
3.0
1.0
0.461
8,050
67.0
88.3
10.3
273
0.0044
0
0.2
0.748
22,750
1.25
91.4
6.0
0
1.0
0.555
12,600
8.64
91.7
8.0
1.1
1.0
0.481
8,050
39.9
90.5
9.9
3.2
1.0
0.440
7,600
77.0
87.5
9.4
287
0.008
0
1.0
0.668
9,600
14.8
92.3
6.4
1.07
1.0
0.517
8,050
39.8
92.0
8.6
3.1
1.0
0.443
7,100
75.0
90.5
9.6
5.0
1.0
0.440
6,600
97.0
87.4
8.0
Table V
Degree of ionization of mercury at a series of temperatures and two different pressures.
αat
T
P=1 atm.
P=100 atm.
5000
1.38×10−4
1.38×10−5
5500
4.65×10−4
4.65×10−5
6000
1.29×10−3
1.29×10−4
6500
3.09×10−3
3.09×10−4
7000
6.59×10−3
6.59×10−4
8000
2.28×10−2
2.28×10−3
9000
7.67×10−2
7.67×10−3
Table VIII
Efficiencies of Lenard phosphors.
Efficiency
Phosphor
λi
λe
Obs.
Calc. forf=1
CaS+Bi
3660
4400
0.82
0.83
4360
4400
0.97
0.99
ZnS+Cu
3660
5150
0.73
0.71
4360
5150
0.84
0.85
CaS+Cu
3660
5250
0.64
0.70
4360
5250
0.76
0.85
Tables (6)
Table I
Luminous efficiencies of various sources of light (lumens per watt). For spectral energy distribution data see references 28, 29a, 29b and 41. Methods of measurement and data are discussed comprehensively in reference 37.
Value given by L. J. Buttolph, reference 41.
A. C. Downes, Elect. Eng. 54, 761 (1935), states that efficiencies as high as 79 L/W have been obtained.
Based on Vλ for D lines.
Value calculated by F. A. Benford from energy distribution.
Calculated from energy-distribution data obtained in this laboratory by G. R. Fonda.
Values obtained by G. E. Inman, Incandescent Lamp Division, General Electric Co., Cleveland, Ohio.
Table II
Total energy and luminous characteristics of a black-body radiator.
T Deg. K
W Watts Per cm2
L Lumens Per cm2
Ls Lumens Per watt
L0 Lumens Per watt
η
2000
91.4
1.40×102
1.53
153
0.01
3000
426.4
8.89×103
19.2
206.7
0.093
4000
1462
7.32×104
50.1
219.6
0.228
5000
3570
2.64×105
73.9
229.3
0.322
5500
5226
4.22×105
82.6
227.9
0.362
6000
7403
6.22×105
84.0
221.1
0.380
6500
10190
8.75×105
86.3
218.5
0.395
7000
13710
11.53×105
84.1
212.9
0.395
Table III
Critical Potentials, Resonance Lines, and Metastable Levels
Atom
Vr
λr
Vm
Vi
Lithium (Li)
1.84
6,708
5.37
Sodium (Na)
2.10
5,890; 5,896
5.12
Potassium (K)
1.60
7,645; 7,699
4.32
Rubidium (Rb)
1.56
7,800; 7,948
4.16
Caesium (Cs)
1.38; 1.45
8,521; 8,943
3.87
Helium (He)
20.91
592
19.77
24.47
21.12
584
20.55
Neon (Ne)
16.58
744
16.53
21.47
16.77
736
16.62
Argon (A)
11.56
1,067
11.49
15.69
11.77
1,048
11.66
Krypton (Kr)
9.98
1,236
9.86
13.94
10.59
1,165
10.51
Xenon (Xe)
8.39
1,469
8.28
12.08
9.52
1,295
9.40
Zinc (Zn)
4.01
3,076
3.99
9.36
5.77
2,139
4.06
Cadmium (Cd)
3.78
3,261
3.71
8.96
5.39
2,288
3.93
Mercury (Hg)
4.87
2,537
4.64
10.38
6.67
1,850
5.44
Thallium (Tl)
3.27
3,776
0.96
6.07
4.46
2,768
Table IV
Data for positive column discharge in sodium and sodium plus neon tube diameter=3.6 cm.
ER
EW
t°C
p(Na) mm
p(Ne) mm
Arc amp.
Gvolts/cm
Te
ne·10−10
Percentage of Total
255
0.0021
0
0.2
0.432
30,950
1.01
92.2
13.3
0
1.0
0.398
19,200
4.55
93.7
13.8
1.0
0.504
9,100
39.9
88.8
12.5
3.0
1.0
0.461
8,050
67.0
88.3
10.3
273
0.0044
0
0.2
0.748
22,750
1.25
91.4
6.0
0
1.0
0.555
12,600
8.64
91.7
8.0
1.1
1.0
0.481
8,050
39.9
90.5
9.9
3.2
1.0
0.440
7,600
77.0
87.5
9.4
287
0.008
0
1.0
0.668
9,600
14.8
92.3
6.4
1.07
1.0
0.517
8,050
39.8
92.0
8.6
3.1
1.0
0.443
7,100
75.0
90.5
9.6
5.0
1.0
0.440
6,600
97.0
87.4
8.0
Table V
Degree of ionization of mercury at a series of temperatures and two different pressures.