"विज्ञान के नियम" सम्पादित करें

उन [[भौतिक नियम|भौतिक नियमों]] को '''विज्ञान के नियम''' कहा जाता है जो सार्वत्रिक (universal) समझे जाते हैं तथा जो भौतिक जगत के अपरिवर्तनशील तथ्य हैं।
{{Dubious|जीव विज्ञानों के बारे में क्या विचार है? और सामाजिक विज्ञानों के बारे में क्या?|date=August 2009}} किन्तु फिर भी, यदि कोई नया तथ्य या साक्ष्य मिलता है जो इस नियम के विरुद्ध हो तो विज्ञान के नियम असत्य सिद्ध हो सकते हैं। "नियम", [[परिकल्पना]] (hypotheses), [[सिद्धान्त]] (theories), [[अभिगृहीत]] (postulates), प्रिंसिपल (principle) आदि से इस मामले में अलग है कि नियम विश्लेषणात्मक कथन (analytic statement) होता है जिसमें प्राय: प्रयोग द्वारा कोई [[नियतांक]] प्राप्त किया गया होता है। किसी सिद्धान्त में कई नियम हो सकते हैं या वह सिद्धान्त किसी नियम से इंगित होता हो सकता है।

== बिहंगम दृष्टि (Overview) ==
एक मोटे अनुमान के अनुसार ब्रह्माण्ड में कोई १८ मूल भौतिक नियम होंगे।
<ref>{{cite book | last = Powell | first = Michael | title = Stuff You Should Have Learned at School | publisher = Barnes & Noble Books | year = 2004 | isbn = 0-7607-6279-1 | url-access = registration | url = https://archive.org/details/stuffyoushouldha00powe }}</ref>
{{col-begin}}
{{col-break}}
'''[[तरल यांत्रिकी]]'''
* [[आर्कीमिडीज सिद्धान्त|आर्कीमिडीज का सिद्धान्त]] (Archimedes’ principle)
'''बल, द्रव्यमान एवं त्वरण'''
* [[केप्लर के ग्रहीय गति के नियम|केप्लर के उपग्रहीय गति के नियम]] (तीन नियम)
* [[न्यूटन के गति नियम|न्यूटन के गति के नियम]] (तीन नियम)
* रिजिड बॉडी (rigid body) की गति के यूलर के नियम
* [[न्यूटन (इकाई)|न्यूटन]] का [[सार्वत्रिक गुरुत्वाकर्षण का नियम]]
{{col-break}}
'''उष्मा, उर्जा एवं ताप'''
* [[न्यूटन का शीतलन का नियम]]
* [[बॉयल का नियम]]
* [[ऊर्जा संरक्षण का नियम|उर्जा संरक्षण का नियम]]
* [[जूल प्रभाव|जूल के नियम]] (जूल का प्रथम एवं द्वितीय नियम)
* [[ऊष्मागतिकी के सिद्धान्त|उष्मागतिकी के नियम]] (चार नियम)
{{col-break}}
'''क्वाण्टम यांत्रिकी'''
* [[अनिश्चितता सिद्धान्त|हाइजेनबर्ग का अनिश्चितता का सिद्धानत]]
{{col-end}}

== संरक्षण के नियम (Conservation laws) ==
संरक्षन के नियम विज्ञान में सर्वाधिक महत्त्व रखते हैं।

* [[द्रव्य की अविनाशिता का नियम 
    द्रव्यमान संरक्षण का नियम(Conservation of mass)
* [[ऊर्जा संरक्षण का नियम|उर्जा संरक्षण का नियम]] (Conservation of energy)
* [[संवेग संरक्षण का नियम]]
* [[कोणीय संवेग के संरक्षण का नियम]]
* [[आवेश के संरक्षण का नियम]]

ये मूल नियम [[स्पेस]], [[समय]] एवं [[कला]] (phase) की समांगता (homogeneity) के परिणाम हैं। [[एमी नीदर का प्रमेय]] (Emmy Noether theorem) देखिये।

== गैस के नियम ==
Other less significant (non fundamental) laws are the mathematical consequences of the above conservation laws for derivative physical quantities (mathematically defined as [[force]], [[pressure]], [[temperature]], [[density]], [[Force field (physics)|force fields]], etc):

* [[Boyle's Law]] ([[pressure]] and [[volume]] of [[ideal gas]])
* [[Law of Charles and Gay-Lussac|Charles & Gay-Lussac]] (gases expand equally with the same change of [[temperature]])
* [[Ideal Gas Law]] ''<math>PV = \ nRT</math>''

== आइंस्टीन के नियम ==

:* [[Energy]] of [[photon]]s - Energy equals [[Planck's constant]] multiplied by the [[frequency]] of the [[light]].
::<math> E \ = hf </math>

: '''[[Special Relativity]]'''
:* Constancy of the [[speed of light]]
:* [[Lorentz transformations]] - Transformations of [[Cartesian coordinate system|Cartesian coordinates]] between relatively moving [[reference frame]]s.
:*: <math>x' = (x - vt) / \sqrt{1 - v^2/c^2}</math>
:*: <math>y' = y</math>
:*: <math>z' = z</math>
:*: <math>t' = (t - vx/c^2) / \sqrt{1 - v^2/c^2}</math>
:* [[E=mc2|Mass-energy equivalence]]
:*: <math> \ E = mc^2 </math> ([[Energy]] = [[mass]] × [[speed of light]]<sup>2</sup>)

: '''[[General Relativity]]'''
:* Energy-momentum (including mass via ''E=mc''<sup>2</sup>) curves spacetime.
:*: This is described by the [[Einstein field equations]]:
:*: <math>R_{ab} - {1 \over 2}R\,g_{ab} = {8 \pi G \over c^4} T_{ab}.</math>
:*: <math>R_{ab}</math> is the [[Ricci tensor]], <math>R</math> is the [[Ricci scalar]], <math>g_{ab}</math> is the [[metric tensor (general relativity)|metric tensor]], <math>T_{ab}</math> is the [[stress-energy tensor]], and the constant is given in terms of <math>\pi</math> ([[pi]]), <math>c</math> (the [[speed of light]]) and <math>G</math> (the [[gravitational constant]]).
:*: <math> \ E=mc^2</math> where <math>m=\frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}</math>

{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}{{अनुवाद}}== न्यूटन के नियम ==
* [[Newton's laws of motion]] - Replaced by [[theory of relativity|relativity]]
:# [[Inertia|Law of Inertia]]
:# <math> \ F = d(\vec p)/dt </math>. Although it implies <math> \ F = ma </math>, that is not necessarily true.
:# <math>F_{ab}=-F_{ba}</math>. Force of a on b equals the [[ऋणात्मक संख्या|negative]] force of b on a, or for every [[action (physics)|action]] there is an equal and opposite [[Reaction (physics)|reaction]].
* [[Law of heat conduction]]
* [[gravity|General law of gravitation]] - [[Gravitational force]] between two objects equals the [[gravitational constant]] times the product of the [[mass]]es divided by the [[distance]] between them squared.
:* <math> F_g = G \frac{m_1m_2} {r^2} </math>
:* This law is really just the low limit solution of [[Einstein's field equations]] and is not accurate with modern high precision gravitational measurements.

== रासायनिक नियम ==
{{Main|Chemical law}}
'''Chemical laws''' are those [[laws of nature]] relevant to [[रसायन विज्ञान|chemistry]]. The most fundamental concept in chemistry is the [[law of conservation of mass]], which states that there is no detectable change in the quantity of matter during an ordinary [[chemical reaction]]. Modern physics shows that it is actually [[energy]] that is conserved, and that energy and mass are [[अल्बर्ट आइंस्टीन#Energy equivalency|related]]; a concept which becomes important in [[nuclear chemistry]]. [[Conservation of energy]] leads to the important concepts of [[Chemical equilibrium|equilibrium]], [[thermodynamics]], and [[chemical kinetics|kinetics]].

Additional laws of chemistry elaborate on the law of conservation of mass. [[Joseph Proust]]'s [[law of definite composition]] says that pure chemicals are composed of elements in a definite formulation; we now know that the structural arrangement of these elements is also important.

[[John Dalton|Dalton]]'s [[law of multiple proportions]] says that these chemicals will present themselves in proportions that are small whole numbers (i.e. 1:2 O:H in water); although in many systems (notably biomacromolecules and minerals) the ratios tend to require large numbers, and are frequently represented as a fraction. 

More modern laws of chemistry define the relationship between energy and transformations. 

* In equilibrium, molecules exist in mixture defined by the transformations possible on the timescale of the equilibrium, and are in a ratio defined by the intrinsic energy of the molecules—the lower the intrinsic energy, the more abundant the molecule.
* Transforming one structure to another requires the input of energy to cross an energy barrier; this can come from the intrinsic energy of the molecules themselves, or from an external source which will generally accelerate transformations. The higher the energy barrier, the slower the transformation occurs.
* There is a hypothetical intermediate, or ''transition structure'', that corresponds to the structure at the top of the energy barrier. The [[Hammond-Leffler Postulate]] states that this structure looks most similar to the product or starting material which has intrinsic energy closest to that of the energy barrier. Stabilizing this hypothetical intermediate through chemical interaction is one way to achieve [[catalysis]].
* All chemical processes are reversible (law of [[microscopic reversibility]]) although some processes have such an energy bias, they are essentially irreversible.

== विद्युतचुम्बकीय नियम (Electromagnetic laws) ==
* [[Coulomb's law]] - [[Force]] between any two [[Electric charge|charges]] is equal to the product of the charges divided by 4 [[pi]] times the [[Permittivity#Vacuum permittivity|vacuum permittivity]] times the [[distance]] squared between the two charges.
:<math> F = \frac{\left|q_1 q_2\right|}{4 \pi \epsilon_0 r^2} </math>
* [[Ohm's Law]]
:<math>
V = I \cdot R
</math>
* [[Kirchhoff's circuit laws]] ([[Current (electricity)|current]] and [[voltage]] laws)
* [[Kirchhoff's law of thermal radiation]]
* [[Maxwell's equations]] ([[electric field|electric]] and [[magnetic field]]s):
{| border="1" style="margin-left: 3em;"
|-
|
{|
|-
||'''Name'''
||'''Partial Differential form'''
|-
||[[Gauss's law]] :
||<math>\nabla \cdot \mathbf{D} = \rho</math>
|-
||
|-
||Gauss's law for magnetism:
||<math>\nabla \cdot \mathbf{B} = 0</math>
|-
||[[Faraday's law of induction]]:
||<math>\nabla \times \mathbf{E} = -\frac{\partial \mathbf{B}} {\partial t}</math>
|-
||[[Ampère's law]] + Maxwell's extension:
||<math>\nabla \times \mathbf{H} = \mathbf{J} + \frac{\partial \mathbf{D}} {\partial t}</math>
|}
|}

== उष्मागतिकीय नियम (Thermodynamic laws) ==
'''[[Thermodynamics]]'''
:* [[Zeroth law of thermodynamics]]
:*: If two systems are in [[thermal equilibrium]] with a third system, then they are in thermal equilibrium with one another.
:* [[First law of thermodynamics]]
:*: The change in energy d''U'' in a system is accounted for entirely by the heat &delta;''Q'' absorbed by the system and the work &delta;''W'' done by the system:
:*:: <math>\mathrm{d}U=\delta Q-\delta W\,</math>
:* [[Second law of thermodynamics]]
:*: <math>\int \frac{\delta Q}{T} \ge 0</math>
:* [[Third law of thermodynamics]]
:*: As the temperature ''T'' of a system approaches absolute zero, the entropy ''S'' approaches a minimum value ''C'': as ''T''&nbsp;&rarr;&nbsp;0, ''S''&nbsp;&rarr;&nbsp;''C''.
:* [[Onsager reciprocal relations]] - sometimes called the ''Fourth Law of Thermodynamics''
:*: <math> \mathbf{J}_{u} = L_{uu}\, \nabla(1/T) - L_{ur}\, \nabla(m/T) \!</math>;
:*: <math> \mathbf{J}_{r} = L_{ru}\, \nabla(1/T) - L_{rr}\, \nabla(m/T) \!</math>.

== क्वाण्टम नियम ==
'''[[प्रमात्रा यान्त्रिकी|क्वाण्टम यांत्रिकी]]'''
:* [[हाइजेनबर्ग का अनिश्चितता का सिद्धान्त]] - [[स्थिति]] की [[अनिश्चितता]] एवं [[संवेग]] की अनिश्चितता का गुणनफल 'परिवर्तित (reduced) प्लैंक नियतांक' के आधे के बराबर या उससे अधिक होता है।
:*: <math>\Delta x \Delta p  \ge \frac{\hbar}{2} </math>
:* [[Matter wave]]length - Laid the foundations of [[particle-wave duality]] and was the key idea in the Schrödinger equation.
:*: <math> \lambda = \frac {hc}{mc^2} = \frac {h}{mc} = \frac {h}{p}</math>
:* [[Schrödinger equation]] - Describes the time dependence of a quantum mechanical system.
:*: <math> H(t) \left| \psi (t) \right\rangle = i \hbar {\partial\over\partial t} \left| \psi (t) \right\rangle</math>
:*: The [[Hamiltonian (quantum mechanics)|Hamiltonian]] ''H''(''t'') is a [[self-adjoint operator]] acting on the state space, <math>\psi (t)</math> is the instantaneous [[state vector]] at time ''t'', ''i'' is the [[imaginary number|unit imaginary number]], <math>\hbar</math> is [[Planck's constant]] divided by 2π

It is thought that the successful integration of [[Einstein's field equations]] with the [[uncertainty principle]] and [[Schrödinger equation]], something no one has achieved so far with a testable [[theory]], will lead to a theory of [[quantum gravity]], the most basic physical law sought after today.

== अन्य नियम ==
* [[Navier-Stokes equations]] of [[fluid dynamics]]
: <math>-\nabla p +
\mu \left(\nabla^2 \mathbf{u} + {1 \over 3} \nabla (\nabla \cdot \mathbf{u}) \right) +
\rho \mathbf{u}
= \rho \left({ \partial\mathbf{u} \over \partial t} +
\mathbf{u} \cdot \nabla \mathbf{u}
\right) </math>
* [[Poiseuille's law]] (voluminal [[laminar]] [[stationary]] flow of [[potential flow|incompressible]] uniform [[viscosity|viscous]] liquid through a cylindrical tube with the constant circular cross-section)
:<math> \Phi_{V} = {\pi r^{4}\over 8 \eta} { \triangle p^{\star} \over l}</math>
* '''[[Radiation|Radiation laws]]'''
:* [[Planck's law of black body radiation]] ([[spectral density]] in a [[radiation]] of a [[black-body]])
:* [[Wien's law]] (wavelength of the peak of the emission of a black body) :''λ<sub>0</sub>T'' = ''k<sub>w</sub>''
:* [[Stefan-Boltzmann law]] (total radiation from a black body)
:*: <math> j^{\star} = \sigma T^4</math>
* [[Laws of Kepler]] ([[planetary motion]])
* [[Beer-Lambert law|Beer-Lambert]] ([[light absorption]])
* [[Dulong-Petit law]] ([[specific heat capacity]] at constant volume)
*: <math> c_V = \frac{3R} {M}</math>
* [[Buys-Ballot's law]] (wind travels counterclockwise around [[low pressure system]]s in the [[Northern Hemisphere]])

== इन्हें भी देखें ==
* [[भौतिक नियम]] (Physical law) - यहाँ इस पर भी चर्चा है कि 'नियम' किसे कहा जाय।
* [[व्यक्तियों के नाम से प्रसिद्ध वैज्ञानिक नियम]]

== टिप्पणी ==
<references />

== इन्हें भी देखें ==
* [[भौतिक प्रभावों की सूची]]

[[श्रेणी:विज्ञान]]
[[श्रेणी:वैज्ञानिक नियम|*]]