भौतिक नियतांक
भौतिक नियतांक (physical constant) उस भौतिक राशि (physical quantity) को कहते हैं जिसके बारे में ऐसा विश्वास किया जाता है कि वह राशि प्रकृति में सार्वत्रिक (universal) है तथा समय के साथ अपरिवर्तनशील या नियत है। भौतिक नियतांक, गणितीय नियतांक से इस मामले में भिन्न हैं कि गणितीय नियतांक संख्यात्मक दृष्टि से तो नियत होते हैं किन्तु उनका किसी मापन से सम्बन्ध नहीं होता।
विज्ञान में बहुत से भौतिक नियतांक हैं जिनमें से प्रमुख हैं - शून्य में प्रकाश का वेग c, गुरुत्वाकर्षण नियतांक G, प्लांक नियतांक h, निर्वात का विद्युत नियतांक ε0, तथा एलेक्ट्रान का आवेश e.
विमासहित एवं विमारहित भौतिक नियतांक (Dimensionful and dimensionless physical constants)
संपादित करेंविस्तृत जानकारी के लिये मूलभूत भौतिक नियतांक देखें।
सार्वत्रिक नियतांकों की सारणी
संपादित करेंQuantity | Symbol | Value | Relative Standard Uncertainty |
---|---|---|---|
speed of light in vacuum | 299 792 458 m·s−1 | defined | |
Newtonian constant of gravitation | 6.67428(67)×१०−11 m3·kg−1·s−2 | 1.0 × 10−4 | |
Planck constant | 6.626 068 96(33) × 10−34 J·s | 5.0 × 10−8 | |
reduced Planck constant | 1.054 571 628(53) × 10−34 J·s | 5.0 × 10−8 |
विद्युतचुम्बकीय नियतांकों की सारणी
संपादित करेंQuantity | Symbol | Value[1] (SI units) | Relative Standard Uncertainty |
---|---|---|---|
magnetic constant (vacuum permeability) | 4π × 10−7 N·A−2 = 1.256 637 061... × 10−6 N·A−2 | defined | |
electric constant (vacuum permittivity) | 8.854 187 817... × 10−12 F·m−1 | defined | |
characteristic impedance of vacuum | 376.730 313 461... Ω | defined | |
Coulomb's constant | 8.987 551 787... × 109 N·m²·C−2 | defined | |
elementary charge | 1.602 176 487(40) × 10−19 C | 2.5 × 10−8 | |
Bohr magneton | 927.400 915(23) × 10−26 J·T−1 | 2.5 × 10−8 | |
conductance quantum | 7.748 091 7004(53) × 10−5 S | 6.8 × 10−10 | |
inverse conductance quantum | 12 906.403 7787(88) Ω | 6.8 × 10−10 | |
Josephson constant | 4.835 978 91(12) × 1014 Hz·V−1 | 2.5 × 10−8 | |
magnetic flux quantum | 2.067 833 667(52) × 10−15 Wb | 2.5 × 10−8 | |
nuclear magneton | 5.050 783 43(43) × 10−27 J·T−1 | 8.6 × 10−8 | |
von Klitzing constant | 25 812.807 557(18) Ω | 6.8 × 10−10 |
परमाणवीय एवं नाभिकीय नियतांकों की सारणी
संपादित करेंQuantity | Symbol | Value[1] (SI units) | Relative Standard Uncertainty | |
---|---|---|---|---|
Bohr radius | 5.291 772 108(18) × 10−11 m | 3.3 × 10−9 | ||
classical electron radius | 2.817 940 2894(58) × 10−15 m | 2.1 × 10−9 | ||
electron mass | 9.109 382 15(45) × 10−31 kg | 5.0 × 10−8 | ||
Fermi coupling constant | 1.166 39(1) × 10−5 GeV−2 | 8.6 × 10−6 | ||
fine-structure constant | 7.297 352 537 6(50) × 10−3 | 6.8 × 10−10 | ||
Hartree energy | 4.359 744 17(75) × 10−18 J | 1.7 × 10−7 | ||
proton mass | 1.672 621 637(83) × 10−27 kg | 5.0 × 10−8 | ||
quantum of circulation | 3.636 947 550(24) × 10−4 m² s−1 | 6.7 × 10−9 | ||
Rydberg constant | 10 973 731.568 525(73) m−1 | 6.6 × 10−12 | ||
Thomson cross section | 6.652 458 73(13) × 10−29 m² | 2.0 × 10−8 | ||
weak mixing angle | 0.222 15(76) | 3.4 × 10−3 |
भौतिक-रासायनिक नियतांकों की सारणी
संपादित करेंQuantity | Symbol | Value[1] (SI units) | Relative Standard Uncertainty | |
---|---|---|---|---|
atomic mass unit (unified atomic mass unit) | 1.660 538 86(28) × 10−27 kg | 1.7 × 10−7 | ||
Avogadro's number | 6.022 141 5(10) × 1023 mol−1 | 1.7 × 10−7 | ||
Boltzmann constant | 1.380 6504(24) × 10−23 J·K−1 | 1.8 × 10−6 | ||
Faraday constant | 96 485.3383(83)C·mol−1 | 8.6 × 10−8 | ||
first radiation constant | 3.741 771 18(19) × 10−16 W·m² | 5.0 × 10−8 | ||
for spectral radiance | 1.191 042 82(20) × 10−16 W·m² sr−1 | 1.7 × 10−7 | ||
Loschmidt constant | at =273.15 K and =101.325 kPa | 2.686 777 3(47) × 1025 m−3 | 1.8 × 10−6 | |
gas constant | 8.314 472(15) J·K−1·mol−1 | 1.7 × 10−6 | ||
molar Planck constant | 3.990 312 716(27) × 10−10 J·s·mol−1 | 6.7 × 10−9 | ||
molar volume of an ideal gas | at =273.15 K and =100 kPa | 2.2710 981(40) × 10−2 m³·mol−1 | 1.7 × 10−6 | |
at =273.15 K and =101.325 kPa | 2.2413 996(39) × 10−2 m³·mol−1 | 1.7 × 10−6 | ||
Sackur-Tetrode constant | at =1 K and =100 kPa | |
−1.151 704 7(44) | 3.8 × 10−6 |
at =1 K and =101.325 kPa | −1.164 867 7(44) | 3.8 × 10−6 | ||
second radiation constant | 1.438 775 2(25) × 10−2 m·K | 1.7 × 10−6 | ||
Stefan-Boltzmann constant | 5.670 400(40) × 10−8 W·m−2·K−4 | 7.0 × 10−6 | ||
Wien displacement law constant | 4.965 114 231... | 2.897 768 5(51) × 10−3 m·K | 1.7 × 10−6 |
स्वीकृत मानों की सारणी (Table of adopted values)
संपादित करेंQuantity | Symbol | Value (SI units) | Relative Standard Uncertainty | |
---|---|---|---|---|
conventional value of Josephson constant[2] | 4.835 979 × 1014 Hz·V−1 | defined | ||
conventional value of von Klitzing constant[3] | 25 812.807 Ω | defined | ||
molar mass | constant | 1 × 10−3 kg·mol−1 | defined | |
of carbon-12 | 1.2 × 10−2 kg·mol−1 | defined | ||
standard acceleration of gravity (gee, free-fall on Earth) | 9.806 65 m·s−2 | defined | ||
standard atmosphere | 101 325 Pa | defined |
प्राकृतिक इकाइयाँ
संपादित करेंUsing dimensional analysis, it is possible combine fundamental physical constants to produce basic units of measurement. Depending on the choice and arrangement of constants used, the resulting natural units may have physical meaning. For example, Planck units use and to derive constants relevant to unified theories, including quantum gravity.
Name | Dimension | Expression | Value[1] (SI units) |
---|---|---|---|
Planck length | Length (L) | 1.616 252(81) × 10−35 m | |
Planck mass | Mass (M) | 2.176 44(11) × 10−8 kg | |
Planck time | Time (T) | 5.391 24(27) × 10−44 s | |
Planck charge | Electric charge (Q) | 1.875 545 870(47) × 10−18 C | |
Planck temperature | Temperature (Θ) | 1.416 785(71) × 1032 K |
टिप्पणियाँ
संपादित करें- ↑ अ आ इ ई The values are given in the so-called concise form; the number in brackets is the standard uncertainty, which is the value multiplied by the relative standard uncertainty.
- ↑ This is the value adopted internationally for realizing representations of the volt using the Josephson effect.
- ↑ This is the value adopted internationally for realizing representations of the ohm using the quantum Hall effect.
सन्दर्भ
संपादित करें- साँचा:CODATA2006
- Barrow, John D., The Constants of Nature; From Alpha to Omega - The Numbers that Encode the Deepest Secrets of the Universe. Pantheon Books, 2002. ISBN 0-375-42221-8.
इन्हें भी देखें
संपादित करेंबाहरी कड़ियाँ
संपादित करें- Sixty Symbols, University of Nottingham
- IUPAC - Gold Book