ভৌত ধ্রুবক

উইকিপিডিয়া, মুক্ত বিশ্বকোষ থেকে

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[সম্পাদনা]

Quantity Symbol Value Relative Standard Uncertainty
characteristic impedance of vacuum Z_0 = \mu_0 c \, 376.730 313 461... Ω defined
electric constant (permittivity of free space) \epsilon_0 = 1 / ( \mu_0 c^2 )\, 8.854 187 817... × 10−12F·m−1 defined
magnetic constant (permeability of free space)  \mu_0 \, 4π × 10−7 N·A−2 = 1.2566 370 614... × 10−6 N·A−2 defined
Newtonian constant of gravitation G \, 6.6742(10) × 10−11m3·kg−1·s−2 1.5 × 10−4
Planck's constant h \, 6.626 0693(11) × 10−34 J·s 1.7 × 10−7
Dirac's constant \hbar = h / (2 \pi) 1.054 571 68(18) × 10−34 J·s 1.7 × 10−7
speed of light in vacuum c \, 299 792 458 m·s−1 defined

তাড়িতচুম্বক ধ্রুবক[সম্পাদনা]

Quantity Symbol Value1 (SI units) Relative Standard Uncertainty
Bohr magneton \mu_B = e \hbar / 2 m_e 927.400 949(80) × 10−26 J·T−1 8.6 × 10-8
conductance quantum G_0 = 2 e^2 / h \, 7.748 091 733(26) × 10−5 S 3.3 × 10−9
Coulomb's constant \kappa = 1 / 4\pi\epsilon_0 \, 8.987 742 438 × 109 N·m2C−2 defined
Josephson constant K_J = 2 e / h \, 483 597.879(41) × 109 Hz· V−1 8.5 × 10−8
magnetic flux quantum \phi_0 = h / 2 e \, 2.067 833 72(18) × 10−15 Wb 8.5 × 10−8
nuclear magneton \mu_N = e \hbar / 2 m_p 5.050 783 43(43) × 10−27 J·T−1 8.6 × 10−8
resistance quantum R_0 = h / 2 e^2 \, 12 906.403 725(43) Ω 3.3 × 10−9
von Klitzing constant R_K = h / e^2 \, 25 812.807 449(86) Ω 3.3 × 10−9

আনবিক ও পারমানবিক ধ্রুবক[সম্পাদনা]

Quantity Symbol Value1 (SI units) Relative Standard Uncertainty
Bohr radius a_0 = \alpha / 4 \pi R_\infin \, 0.529 177 2108(18) × 10−10 m 3.3 × 10−9
Fermi coupling constant G_F / (\hbar c)^3 1.166 39(1) × 10−5 GeV−2 8.6 × 10−6
fine-structure constant \alpha = \mu_0 e^2 c / (2 h) = e^2 / (4 \pi \epsilon_0 \hbar c) \, 7.297 352 568(24) × 10−3 3.3 × 10−9
Hartree energy E_h = 2 R_\infin h c \, 4.359 744 17(75) × 10−18 J 1.7 × 10−7
quantum of circulation h / 2 m_e \, 3.636 947 550(24) × 10−4 m2 s−1 6.7 × 10−9
Rydberg constant R_\infin = \alpha^2 m_e c / 2 h \, 10 973 731.568 525(73) m−1 6.6 × 10−12
Thomson cross section (8 \pi / 3)r_e^2 0.665 245 873(13) × 10−28 m2 2.0 × 10−8
weak mixing angle \sin^2 \theta_W = 1 - (m_W / m_Z)^2 \, 0.222 15(76) 3.4 × 10−3

গাঠনিক রসায়নের ধ্রুবক[সম্পাদনা]

Quantity Symbol Value1 (SI units) Relative Standard Uncertainty
atomic mass constant (unified atomic mass unit) m_u = 1 \ u \, 1.660 538 86(28) × 10−27 kg 1.7 × 10−7
Avogadro's number N_A, L \, 6.022 1415(10) × 1023 1.7 × 10−7
Boltzmann constant k = R / N_A \, 1.380 6505(24) × 10−23 J·K−1 1.8 × 10−6
Faraday constant F = N_A e \, 96 485.3383(83)C·mol−1 8.6 × 10−8
first radiation constant c_1 = 2 \pi h c^2 \, 3.741 771 38(64) × 10−16 W·m2 1.7 × 10−7
for spectral radiance c_{1L} \, 1.191 042 82(20) × 10−16 W · m2 sr−1 1.7 × 10−7
Loschmidt constant at T=273.15 K and p=101.325 kPa n_0 = N_A / V_m \, 2.686 7773(47) × 1025 m−3 1.8 × 10−6
gas constant R \, 8.314 472(15) J·K−1·mol−1 1.7 × 10−6
molar Planck constant N_A h \, 3.990 312 716(27) × 10−10 J · s · mol−1 6.7 × 10−9
molar volume of an ideal gas at T=273.15 K and p=100 kPa V_m = R T / p \, 22.710 981(40) × 10−3 m3 ·mol−1 1.7 × 10−6
at T=273.15 K and p=101.325 kPa 22.413 996(39) × 10−3 m3 ·mol−1 1.7 × 10−6
Sackur-Tetrode constant at T=1 K and p=100 kPa S_0 / R = \frac{5}{2}
 + \ln\left[ (2\pi m_u k T / h^2)^{3/2} k T / p \right]
-1.151 7047(44) 3.8 × 10−6
at T=1 K and p=101.325 kPa -1.164 8677(44) 3.8 × 10−6
second radiation constant c_2 = h c / k \, 1.438 7752(25) × 10−2 m·K 1.7 × 10−6
Stefan-Boltzmann constant \sigma = (\pi^2 / 60) k^4 / \hbar^3 c^2 5.670 400(40) × 10−8 W·m−2·K−4 7.0 × 10−6
Wien displacement law constant b = (h c / k) /   \, 4.965 114 231... 2.897 7685(51) × 10−3 m · K 1.7 × 10−6

Table of adopted values[সম্পাদনা]

Quantity Symbol Value (SI units) Relative Standard Uncertainty
conventional value of Josephson constant2 K_{J-90} \, 483 597.9 × 109 Hz · V−1 defined
conventional value of von Klitzing constant3 R_{K-90} \, 25 812.807 Ω defined
molar mass constant M_u = M(\,^{12}\mbox{C}) / 12 1 × 10−3 kg · mol−1 defined
of carbon-12 M(\,^{12}\mbox{C}) = N_A m(\,^{12}\mbox{C}) 12 × 10−3 kg · mol−1 defined
standard acceleration of gravity (gee, free fall on Earth) g_n \,\! 9.806 65 m·s−2 defined
standard atmosphere  \mbox{atm} \, 101 325 Pa defined

মন্তব্য[সম্পাদনা]

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.

আরও দেখুন[সম্পাদনা]

সহপাঠ্য[সম্পাদনা]

তথ্যসূত্র[সম্পাদনা]

  • CODATA Recommendations - 2002 CODATA Internationally recommended values of the Fundamental Physical Constants