ভৌত ধ্রুবক

পদার্থবিজ্ঞানে, একটি ভৌত ধ্রুবক হল একটি ভৌত রাশির মান যা সার্বজনীন হিসেবে গৃহিত হয় এবং বিশ্বাস করা হয় যে এর মান সময়ের সাথে পরিবর্তিত হয় নাা।

সার্বজনীন ধ্রুবক
QuantitySymbolValueRelative Standard Uncertainty
characteristic impedance of vacuum376.730 313 461... Ωdefined
electric constant (permittivity of free space)8.854 187 817... × 10−12F·m−1defined
magnetic constant (permeability of free space)4π × 10−7 N·A−2 = 1.2566 370 614... × 10−6 N·A−2defined
Newtonian constant of gravitation6.6742(10) × 10−11m3·kg−1·s−21.5 × 10−4
Planck's constant6.626 0693(11) × 10−34 J·s1.7 × 10−7
Dirac's constant1.054 571 68(18) × 10−34 J·s1.7 × 10−7
speed of light in vacuum299 792 458 m·s−1defined

তাড়িতচুম্বক ধ্রুবক
QuantitySymbolValue1 (SI units)Relative Standard Uncertainty
Bohr magneton927.400 949(80) × 10−26 J·T−18.6 × 10-8
conductance quantum7.748 091 733(26) × 10−5 S3.3 × 10−9
Coulomb's constant8.987 742 438 × 109 N·m2C−2defined
Josephson constant483 597.879(41) × 109 Hz· V−18.5 × 10−8
magnetic flux quantum2.067 833 72(18) × 10−15 Wb8.5 × 10−8
nuclear magneton5.050 783 43(43) × 10−27 J·T−18.6 × 10−8
resistance quantum12 906.403 725(43) Ω3.3 × 10−9
von Klitzing constant25 812.807 449(86) Ω3.3 × 10−9

আণবিক ও পারমাণবিক ধ্রুবক
QuantitySymbolValue1 (SI units)Relative Standard Uncertainty
Bohr radius0.529 177 2108(18) × 10−10 m3.3 × 10−9
Fermi coupling constant1.166 39(1) × 10−5 GeV−28.6 × 10−6
fine-structure constant7.297 352 568(24) × 10−33.3 × 10−9
Hartree energy4.359 744 17(75) × 10−18 J1.7 × 10−7
quantum of circulation3.636 947 550(24) × 10−4 m2 s−16.7 × 10−9
Rydberg constant10 973 731.568 525(73) m−16.6 × 10−12
Thomson cross section0.665 245 873(13) × 10−28 m22.0 × 10−8
weak mixing angle0.222 15(76) 3.4 × 10−3

গাঠনিক রসায়নের ধ্রুবক
QuantitySymbolValue1 (SI units)Relative Standard Uncertainty
atomic mass constant (unified atomic mass unit)1.660 538 86(28) × 10−27 kg1.7 × 10−7
Avogadro's number6.022 1415(10) × 10231.7 × 10−7
Boltzmann constant1.380 6505(24) × 10−23 J·K−11.8 × 10−6
Faraday constant96 485.3383(83)C·mol−18.6 × 10−8
first radiation constant3.741 771 38(64) × 10−16 W·m21.7 × 10−7
for spectral radiance1.191 042 82(20) × 10−16 W · m2 sr−11.7 × 10−7
Loschmidt constantat =273.15 K and =101.325 kPa2.686 7773(47) × 1025 m−31.8 × 10−6
gas constant8.314 472(15) J·K−1·mol−11.7 × 10−6
molar Planck constant3.990 312 716(27) × 10−10 J · s · mol−16.7 × 10−9
molar volume of an ideal gasat =273.15 K and =100 kPa22.710 981(40) × 10−3 m3 ·mol−11.7 × 10−6
at =273.15 K and =101.325 kPa22.413 996(39) × 10−3 m3 ·mol−11.7 × 10−6
Sackur-Tetrode constantat =1 K and =100 kPa
-1.151 7047(44)3.8 × 10−6
at =1 K and =101.325 kPa-1.164 8677(44)3.8 × 10−6
second radiation constant1.438 7752(25) × 10−2 m·K1.7 × 10−6
Stefan-Boltzmann constant5.670 400(40) × 10−8 W·m−2·K−47.0 × 10−6
Wien displacement law constant 4.965 114 231...2.897 7685(51) × 10−3 m · K1.7 × 10−6

Table of adopted values
QuantitySymbolValue (SI units)Relative Standard Uncertainty
conventional value of Josephson constant2483 597.9 × 109 Hz · V−1defined
conventional value of von Klitzing constant325 812.807 Ωdefined
molar massconstant1 × 10−3 kg · mol−1defined
of carbon-1212 × 10−3 kg · mol−1defined
standard acceleration of gravity (gee, free fall on Earth)9.806 65 m·s−2defined
standard atmosphere101 325 Padefined

মন্তব্য

1The 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.
2This is the value adopted internationally for realizing representations of the volt using the Josephson effect.
3This is the value adopted internationally for realizing representations of the ohm using the quantum Hall effect.

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