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Converters  Constants  Calculator  Analytical Geometry 

Symbol  Name and Details  Value 
G  Newtonian constant of gravitation  \(6.6743\times 10^{{−11}} \text{m}^3 \cdot \text{kg}^{−1}\cdot \text{s}\) 
Also known as the Gravitational constant, it refers to the attractive force acting between two point particles of mass \(1kg\) seperated at \(1m\) distance.  
\(c\)  Speed of light in vacuum  \(299792458\hspace{0.3cm} \text{m}\cdot \text{s}^{−1}\) 
It is the distance that the light travels within one second in vacuum. The speed can be determined more accurately through the equation $$ c=\frac {1}{\sqrt{\mu_0 \epsilon_0}} $$ derived from Maxwell's electromagnetic theory. Here, \(\mu_0\) is the relative magnetic permeability in vacuum and \(\epsilon_0\) is the electric permittivity of vacuum.  
\(h\)  Planck constant  \(6.62607015\times 10^{−34}\hspace{0.3cm} \text{J}\cdot \text{s}\) 
This constant depicts the relationship between the energy of a photon and its frequency $$E=hf$$ It is also used in the equation of uncertainty principle and that of momentum of photon $$p_{photon}=\frac{h}{\lambda}$$  
\(\hbar\)  Reduced Planck constant  \(1.054571817\times 10 ^{−34}\hspace{0.3cm} \text{J}\cdot \text{s}\) 
Also known as the Dirac constant (named after scientist Paul Dirac), it is simply the reduced form of Planck constant, as given by the equation: $$ \hbar= \frac{h}{2\pi} $$  
\(\mu_0\)  Vacuum Magnetic Permeability  \(1.25663706212\times 10^{−6}\hspace{0.3cm} \text{N}\cdot \text{A}^{−2}\) 
This constant quantifies the strength of any magnetic field produced from current in magnetic field.  
\(Z_0\)  Characteristic Impedence of Vacuum  \(376.730313668\hspace{0.3cm} \Omega\) 
According to definition, this constant is the ratio of electric fields and the magnetic fields of any kind of electromagnetic radiation in space, as described by the equation: $$Z_0=\frac{E}{H}$$ or $$Z_0=\mu_0 c$$  
\(\epsilon_0\)  Vacuum Electric Permittivity  \(8.8541878128\times10^{−12}\hspace{0.3cm}\text{F}\cdot\text{m}^{−1}\) 
The constant is the absolute dielectric permittivity of classical vacuum. It can be written in the form of an equation $$\epsilon_0=\frac{1}{\mu_0 c^2} $$  
\(k_B\)  Boltzmann Constant  \(1.380649\times 10^{−23} \hspace{0.3cm}\text{J}\cdot \text{K}^{−1}\) 
It relates the energy of any atom to its absolute Temperature through the equation: $$ E=\frac {1}{2} f k_B T $$ where \(f\) is the degree of freedom of that atom.  
\(\Lambda\)  Cosmological Constant  \(1.1056\times 10^{−52} \hspace{0.3cm}m^{−2}\) 
Also called the Einstein's cosmological constant, in cosmology, the constant coefficient of a term that Albert Einstein temporarily added to his field equations of general relativity but later removed it.  
\(\sigma\)  StefanBoltzmann Constant  \(5.6703744\times 10^{−8}\hspace{0.3cm} \text{W}\cdot \text{m}^{−2}\cdot \text{K}^{−4}\) 
The constant relates the power emitted from a substance to its absolute Temperature to the power 4, as given by the StefanBoltzmann equation: $$P=\sigma \epsilon A T^4 $$ where \(\sigma\) is the aforementioned constant and \(\epsilon\) is the emissitivity of the substance. It can be further formulated as: $$ \sigma=\frac{2 \pi^5 k^4}{15 c^2 h^3}$$  
\(c_1\)  First Radiation Constant  \(3.741771×10^{−16} \hspace{0.3cm}W\cdot m^2\) 
Derived from Planck's law, the constant is the value \(c_1=2\pi hc^2\). It is a constant used in the law.  
\(c_2\)  Second Radiation Constant  \(1.43877×10^{−2}\hspace{0.3cm} \text{m}\cdot \text{K}\) 
Another constant used in the Planck's radiation law, it is value of \(c_2=\frac{hc}{k_B}\).  
\(c_{1L}\)  First Radiation Constant for Spectral Radiance  \(1.191042×10^{−16} \hspace{0.3cm}\text{W}\cdot \text{m}^2\cdot \text{sr}^{−1}\) 
It's simply the first Radiation Constant per unit steridian angle, which means \(c_{1L}=\frac{c_1}{\pi}\).  
\(b\)  Wien wavelength displacement law constant  \(2.89777×10^{−3} \hspace{0.3cm}m\cdot K\) 
According to Wien's displacement law, a formulation is stated that the the spectral radiance of blackbody radiation per unit wavelength, peaks at the wavelength given by the equation: \(\lambda_{peak}=\frac{b}{T}\) where \(T\) is the absolute Temperature of that body.  
\(b'\)  Wien frequency displacement law constant  \(5.878925×10^{10} \hspace{0.3cm}\text{Hz}\cdot \text{K}^{−1}\) 
According to Wien's displacement law, the constant can be formulated as \(b'=\frac {xk_B}{h}\), where \(x=2.821\) is the value for the maxima of Planck's radiation law and \(k_B\) is the Boltzmann constant.  
\(e\)  Elementary Charge  \(1.60217×10^{−19} \hspace{0.3cm}\text{C}\) 
The charge of an electron or a proton, the least charge a particle can have and any more charges on the body must be quantized by this value.  
\(G_0\)  Conductance Quantum  \(7.748091×10^{−5}\hspace{0.3cm}\text{S}\) 
Formulated by the equation \(G_0=\frac{2e^2}{h}\), the constant is the quantized unit of electrical conductance and a key point of Landauer formula  
\(R_K\)  von Klitzing constant  \(25812.807 \hspace{0.3cm}\Omega\) 
Formulated by the equation \(R_K=\frac{h}{e^2}\), it is a multiple of Hall Resistance \(R_{xy}\) as seen in classical Hall effect.  
\(K_J\)  Josephson constant  \(483597.8484×10^9\hspace{0.3cm} \text{Hz}\cdot \text{V}^{−1}\) 
It is the inverse of magnetic flux quantum, as given by the equation \(\frac{2e}{h}\).  
\(\alpha\)  Fine structure Constant  \(7.2973525693\times 10^{−3}\) 
Formulated by the equation \(\alpha=\frac{e^2}{4\pi\epsilon_0 \hbar c}\), it is the ratio of speed of light and electron in the Bohr orbit, the first orbit in a Hydrogen atom.  
\(m_e\)  Mass of an electron  \(9.10938\times 10^{−31}\hspace{0.3cm}\text{kg}\) 
The mass of a static electron, also called the invariant mass.  
\(m_p\)  Mass of a proton  \(1.672621\times 10^{−27}\hspace{0.3cm} \text{kg}\) 
The mass of a static proton, also called the invariant mass.  
\(m_n\)  Mass of a neutron  \(1.67492\times 10^{−27}\hspace{0.3cm} \text{kg}\) 
The mass of a static neutron, also called the invariant mass.  
\(m_{\tau}\)  Mass of a tau  \(3.165\times 10^{−27}\hspace{0.3cm} \text{kg}\) 
The mass of a static tau, also called the invariant mass.  
\(m_t\)  Mass of a top quark  \(3.0784\times 10^{−27}\hspace{0.3cm} \text{kg}\) 
The mass of a static top quark, also called the invariant mass.  
\(m_p\)  Mass of a muon  \(1.883531627\times 10^{−27}\hspace{0.3cm} \text{kg}\) 
The mass of a static muon, also called the invariant mass.  
\(m_p\)  Mass of a Top Quark  \(1.672621\times 10^{−27}\hspace{0.3cm} \text{kg}\) 
The mass of a static top quark, also called the invariant mass.  
\(\frac{m_p}{m_e}\)  Proton to electron mass ratio  \(1826.152\hspace{0.3cm}\) 
The dimensionless constant has a different story to tell you.  
\(\frac{m_W}{m_Z}\)  WZ mass ratio  \(0.88153\) 
The ratio of massses of two particles, the vector bosons Wboson and Zboson  
\(\theta_W\)  Weak Mixing Angle  \(0.2290\) 
The weak mixing angle or Weinberg angle is a parameter in the Weinberg–Salam theory of the electroweak interaction, part of the Standard Model of particle physics, and is usually derived from the formula: $$\sin^2\theta_W=1\left(\frac{m_W}{m_Z}\right)^2$$  
\(g_e\)  Electron gfactor  \(−2.002319\) 
A gfactor (also called g value) is a dimensionless quantity that relates the magnetic moment and angular momentum of an atom, a particle or the nucleus. It is essentially a proportionality constant that relates the different observed magnetic moments \(\mu\) of a particle to their angular momentum quantum numbers and a unit of magnetic moment (to make it dimensionless), usually the Bohr magneton or nuclear magneton through a equation, which is, in most general cases: $$ \mu=g \frac{e}{2m}S$$ where \(S\) is the spin angular momentum of the particle.  
\(g_p\)  Proton gfactor  \(5.585694\) 
A gfactor (also called g value) is a dimensionless quantity that relates the magnetic moment and angular momentum of an atom, a particle or the nucleus. It is essentially a proportionality constant that relates the different observed magnetic moments \(\mu\) of a particle to their angular momentum quantum numbers and a unit of magnetic moment (to make it dimensionless), usually the Bohr magneton or nuclear magneton through a equation, which is, in most general cases: $$\mu=g \frac{e}{2m}S$$ where \(S\) is the spin angular momentum of the particle.  
\(g_{\mu}\)  Muon gfactor  \(2.002331\) 
A gfactor (also called g value) is a dimensionless quantity that relates the magnetic moment and angular momentum of an atom, a particle or the nucleus. It is essentially a proportionality constant that relates the different observed magnetic moments \(\mu\) of a particle to their angular momentum quantum numbers and a unit of magnetic moment (to make it dimensionless), usually the Bohr magneton or nuclear magneton through a equation, which is, in most general cases: $$\mu=g \frac{e}{2m}S$$ where \(S\) is the spin angular momentum of the particle.  
\({\mu_B}\)  Bohr magneton  \(9.2740100×10^{−24}\hspace{0.3cm}\text{J}\cdot \text{T}^{1}\) 
In atomic physics, Bohr magneton is a physical constant and the natural unit for expressing the magnetic moment of an electron caused by its orbital or spin angular momentum. In SI units, the Bohr magneton is defined as: $$\mu_B=\frac{eh}{4\pi m_e}$$ while in Gaussian unit, it is just divided by \(c\), the speed of light. $$\mu_B=\frac{eh}{4\pi m_e c}$$  
\({\mu_N}\)  Nuclear magneton  \(5.0507837461×10{−27}\hspace{0.3cm}\text{J}\cdot \text{T}^{1}\) 
In atomic physics, Nuclear magneton is a physical constant and the natural unit for expressing the magnetic moment of an proton caused by its orbital or spin angular momentum. In SI units, the Nuclear magneton is defined as: $$\mu_B=\frac{eh}{4\pi m_p}$$ while in Gaussian unit, it is just divided by \(c\), the speed of light. $$\mu_B=\frac{eh}{4\pi m_p c}$$  
\(r_e\)  Classical Electron Radius  \(2.8179403×10^{−15}\hspace{0.3cm}\text{m}\) 
Through a simple equation, we can find the value of this constant: $$r_e=\frac{e^2 k_e}{m_e c^2}$$ where \(k_e\) is the Coulomb constant \(k_e=9\times 10^9\hspace{0.3cm} \text{kg m}^3 \text{s}^{2}\cdot \text{C}^{2}\). If we consider that the total electrostatic energy of nucleus of a Hydrogen atom is equal to the Equivalent Mass in it as energy, then we can write the above equation.  
\(\sigma_e\)  Thomson cross section  \(6.6524587×10^{−29}\hspace{0.3cm} \text{m}^2\) 
A cross section of a measure of the probability that a specific process will take place when some kind of radiant excitation intersects a localized phenomenon. Thomson cross section is a constant related to Thomson scattering as derived from the equation: $$\sigma _e=\frac{8\pi}{3}r_e^2$$  
\(a_0\)  Bohr Radius  \(5.2917721×10^{−11}\hspace{0.3cm} \text{m}\) 
The Bohr radius is a physical constant, approximately equal to the most probable distance between the nucleus and the electron in a hydrogen atom in its ground state. It is named after Niels Bohr, due to its role in the Bohr model of an atom.  
\(E_h\)  Hartree Energy  \(4.35974×10^{−18}\hspace{0.3cm} \text{J}\) 
The Hartree, also known as the Hartree energy, is the unit of energy in the Hartree atomic units system, named after the British physicist Douglas Hartree. It can be explained as an equation: $$E_h=\frac{hc\alpha}{2\pi a_0}$$ where \(\alpha\) is the finestructure constant.  
\(R_y\)  Rydberg Unit of Energy  \(2.17987236×10^{−18}\hspace{0.3cm} \text{J}\) 
According to Bohr model, this energy is the equivalent amount of energy in a Rydberg constant. As the equation goes, $$ R_y=hcR_{\infty}=\frac{e^2}{8\pi\epsilon_0 a} $$ where \(R_{\infty}\) is the Rydberg Constant.  
\(R_{\infty}\)  Rydberg Constant  \( 10973731.568\hspace{0.3cm}\text{m}^{−1}\) 
It can be described according to the equation:$$R_{\infty}=\frac{m_e e^4}{8\epsilon_0^2 h^3 c}$$ It is simply a parameter that describes the frequency of radiation of atomic spectra found in a Hydrogen Atom, used in the Rydberg equation of wave number:$$\frac{1}{\lambda}=R_H\left(\frac{1}{n_1^2}\frac{1}{n_2^2}\right)$$ where the electron has moved from \(n_2\) to \(n_1\) in either way.  
\(N_A\)  Avogadro Constant  \(6.0221\times 10^{23}\hspace{0.3cm} \text{mol}^{−1}\) 
It is the number of constituent particles in one mole of a substance.  
\(R\)  Molar Gas Constant  \(8.3144626\hspace{0.3cm}\text{J}\cdot \text{mol}^{−1}\cdot \text{K}^{1}\) 
The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per amount of substance. The constant is also a combination of the constants from Boyle's law, Charles's law, Avogadro's law, and GayLussac's law. It is a physical constant that is featured in many fundamental equations in the physical sciences, such as the ideal gas law, the Arrhenius equation, and the Nernst equation. Can be furthur written in the form of: $$R=N_A k_B$$  
\(F\)  Faraday Constant  \(96485.332\hspace{0.3cm} \text{C}\cdot \text{mol}^{−1}\) 
The constant is the electric charge of one mole of any Elementary charge, given by the equation: $$F=N_A e$$  
\(m(^{12}C)\)  Atomic mass of Carbon12  \(1.992646\times 10^{−26} \hspace{0.3cm} \text{kg}\) 
The mass of an atom of the C12 isotope  
\(M ^{12}C\)  Molar mass of Carbon12  \(11.999999\times 10^{−3}\hspace{0.3cm} \text{kg}\cdot \text{mol}^{−1}\) 
The mass of one mole atom of C12 isotope. $$\text{M}^{12}C=\text{N_A m}^{12}\text{C}$$  
\(m_u\)  Molar mass constant  \(0.999999\times 10^{−3}\hspace{0.3cm} \text{kg}\cdot \text{mol}^{−1}\) 
The molar mass constant is considered to be onetwelfth of the molar mass of C12. Which means \(m_u=\frac{M ^{12}C}{12}\). The molar mass of any element or compound is its relative atomic mass (atomic weight) multiplied by the molar mass constant.  
\(\Delta \nu _{Cs}\)  Hyperfine Transition Frequency of Cs133  \(9192631770\hspace{0.3cm}\text{Hz}\) 
The constant detail leads to here. 
Universal  
\(h\)  Planck constant  \(6.62607015\times \hspace{0.3cm}10^{−34} \text{J}\cdot \text{s}\) 
This constant depicts the relationship between the energy of a photon and its frequency $$E=hf$$ It is also used in the equation of uncertainty principle and that of momentum of photon $$p_{photon}=\frac{h}{\lambda}$$  
\(\hbar\)  Reduced Planck constant  \(1.054571817\times 10 ^{−34}\hspace{0.3cm} \text{J}\cdot \text{s}\) 
Also known as the Dirac constant (named after scientist Paul Dirac), it is simply the reduced form of Planck constant, as given by the equation: $$ \hbar= \frac{h}{2\pi} $$  
\(c\)  Speed of light in vacuum  \(299792458\hspace{0.3cm} \text{m}\cdot \text{s}^{−1}\) 
It is the distance that the light travels within one second. The speed can be determined more accurately through the equation $$ c=\frac {1}{\sqrt{\mu_0 \epsilon_0}} $$ derived from Maxwell's electromagnetic theory. Here, \(\mu_0\) is the relative magnetic permeability in vacuum and \(\epsilon_0\) is the electric permittivity of vacuum.  
\(\epsilon_0\)  Vacuum Electric Permittivity  \(8.8541878128\times\hspace{0.3cm}10^{−12} \text{F} \cdot \text{m}^{−1}\) 
The constant is the absolute dielectric permittivity of classical vacuum. It can be written in the form of an equation $$\epsilon_0=\frac{1}{\mu_0 c^2} $$  
\(\mu_0\)  Vacuum Magnetic Permeability  \(1.25663706212\times 10^{−6}\hspace{0.3cm} \text{N}\cdot \text{A}^{−2}\) 
This constant quantifies the strength of any magnetic field produced from current in magnetic field.  
\(Z_0\)  Characteristic Impedence of Vacuum  \(376.730313668\hspace{0.3cm} \Omega\) 
According to definition, this constant is the ratio of electric fields and the magnetic fields of any kind of electromagnetic radiation in space, as described by the equation: $$Z_0=\frac{E}{H}$$ or $$Z_0=\mu_0 c$$  
G  Newtonian constant of gravitation  \(6.6743\times 10^{{−11}} \text{m}^3 \cdot \text{kg}^{−1}\cdot \text{s}\) 
Also known as the Gravitational constant, it refers to the attractive force acting between two point particles of mass \(1kg\) seperated at \(1m\) distance.  
\(l_p\)  Planck Length  \(1.616255\times 10^{−35}\hspace{0.3cm}\text{m}\) 
When the unit of length \(l\) is expressed in terms of any of the four universal physical constants, the Universal Gravitational Constant \(G\), reduced Planck constant \(\hbar\), speed of light \(c\) and Boltzmann constant \(k_B\) it signifies the equation: $$l_p=\sqrt{\frac{\hbar G}{c^3}}$$  
\(t_p\)  Planck Time  \(5.39106\times 10^{−44}\hspace{0.3cm}\text{s}\) 
When the unit of time \(t\) is expressed in terms of any of the four universal physical constants, the Universal Gravitational Constant \(G\), reduced Planck constant \(\hbar\), speed of light \(c\) and Boltzmann constant \(k_B\) it signifies the equation: $$t_p=\sqrt{\frac{\hbar G}{c^3}}$$  
Electromagnetic  
\({\mu_N}\)  Nuclear magneton  \(5.0507837461×10{−27}\hspace{0.3cm}\text{J}\cdot \text{T}^{1}\) 
In atomic physics, Nuclear magneton is a physical constant and the natural unit for expressing the magnetic moment of an proton caused by its orbital or spin angular momentum. In SI units, the Nuclear magneton is defined as: $$\mu_B=\frac{eh}{4\pi m_p}$$ while in Gaussian unit, it is just divided by \(c\), the speed of light. $$\mu_B=\frac{eh}{4\pi m_p c}$$  
\({\mu_B}\)  Bohr magneton  \(9.2740100×10^{−24}\hspace{0.3cm}\text{J}\cdot \text{T}^{1}\) 
In atomic physics, Bohr magneton is a physical constant and the natural unit for expressing the magnetic moment of an electron caused by its orbital or spin angular momentum. In SI units, the Bohr magneton is defined as: $$\mu_B=\frac{eh}{4\pi m_e}$$ while in Gaussian unit, it is just divided by \(c\), the speed of light. $$\mu_B=\frac{eh}{4\pi m_e c}$$  
\(e\)  Elementary Charge  \(1.60217×10^{−19} \hspace{0.3cm}\text{C}\) 
The charge of an electron or a proton, the least charge a particle can have and any more charges on the body must be quantized by this value.  
\(phi_0\)  Magnetic Flux Quantum  \(2.067833×10^{−15} \hspace{0.3cm}\text{C}^{1}\) 
A constant that is the inverse of magnetic flux quantum, as given by the equation \(\frac{h}{2e}\).  
\(G_0\)  Conductance Quantum  \(7.748091×10^{−5}\hspace{0.3cm}\text{S}\) 
Formulated by the equation \(G_0=\frac{2e^2}{h}\), the constant is the quantized unit of electrical conductance and a key point of Landauer formula  
\(K_J\)  Josephson constant  \(483597.8484×10^9\hspace{0.3cm} \text{Hz}\cdot \text{V}^{−1}\) 
It is the inverse of magnetic flux quantum, as given by the equation \(\frac{2e}{h}\).  
\(R_K\)  von Klitzing constant  \(25812.807 \hspace{0.3cm}\Omega\) 
Formulated by the equation \(R_K=\frac{h}{e^2}\), it is a multiple of Hall Resistance \(R_{xy}\) as seen in classical Hall effect.  
AtomicNuclear  
\(m_p\)  Mass of a proton  \(1.672621\times 10^{−27}\hspace{0.3cm} kg\) 
The mass of a static proton, also called the invariant mass.  
\(m_n\)  Mass of a neutron  \(1.67492\times 10^{−27}\hspace{0.3cm} kg\) 
The mass of a static neutron, also called the invariant mass.  
\(m_e\)  Mass of an electron  \(9.10938\times 10^{−31}\hspace{0.3cm}kg\) 
The mass of a static electron, also called the invariant mass.  
\(m_p\)  Mass of a muon  \(1.883531627\times 10^{−27}\hspace{0.3cm} kg\) 
The mass of a static muon, also called the invariant mass.  
\(a_0\)  Bohr Radius  \(5.2917721×10^{−11}\hspace{0.3cm} m\) 
The Bohr radius is a physical constant, approximately equal to the most probable distance between the nucleus and the electron in a hydrogen atom in its ground state. It is named after Niels Bohr, due to its role in the Bohr model of an atom.  
\(\alpha\)  Fine structure Constant  \(7.2973525693\times 10^{−3}\) 
Formulated by the equation \(\alpha=\frac{e^2}{4\pi\epsilon_0 \hbar c}\), it is the ratio of speed of light and electron in the Bohr orbit, the first orbit in a Hydrogen atom.  
\(r_e\)  Classical Electron Radius  \(2.8179403×10^{−15}\hspace{0.3cm}m\) 
Through a simple equation, we can find the value of this constant: $$r_e=\frac{e^2 k_e}{m_e c^2}$$ where \(k_e\) is the Coulomb constant \(k_e=9\times 10^9\hspace{0.3cm} kg m^3 s^{2}\cdot C^{2}\). If we consider that the total electrostatic energy of nucleus of a Hydrogen atom is equal to the Equivalent Mass in it as energy, then we can write the above equation.  
\(\lambda_c\)  Compton Wavelength  \(2.42631023\times10^{12}\) 
The Compton wavelength is a quantum mechanical property of a particle, defined as the wavelength of a photon whose energy is the same as the rest energy of that particle. It was introduced by Arthur Compton in 1923 in his explanation of the scattering of photons by electrons (a process known as Compton scattering). The standard Compton wavelength \(\lambda\) of a particle is given by $$\lambda=\frac{h}{mc}$$  
\(\gamma_p\)  Proton's Gyromagnetic ratio  \(267.5222005\times10^6\hspace{0.3cm}T^{1}\cdot s^{1}\) 
In physics, the gyromagnetic ratio (also sometimes known as the magnetogyric ratio) of a particle or system is the ratio of its magnetic moment to its angular momentum. The term gyromagnetic ratio is often used as a synonym for a different but closely related quantity, the gfactor. The gfactor only differs from the gyromagnetic ratio in being dimensionless. It's governed by the equation: $$\gamma=\frac{q}{2m} $$  
\(\lambda_{cp}\)  Compton Wavelength of a Proton  \(1.3214098\times10^{15}\) 
The Compton wavelength is a quantum mechanical property of a particle, defined as the wavelength of a photon whose energy is the same as the rest energy of that particle. It was introduced by Arthur Compton in 1923 in his explanation of the scattering of photons by electrons (a process known as Compton scattering). The standard Compton wavelength \(\lambda\) of a proton is given by $$\lambda=\frac{h}{m_pc} $$  
\(\lambda_{cn}\)  Compton Wavelength of a Neuton  \(1.3195909\times10^{15}\) 
The Compton wavelength is a quantum mechanical property of a particle, defined as the wavelength of a photon whose energy is the same as the rest energy of that particle. It was introduced by Arthur Compton in 1923 in his explanation of the scattering of photons by electrons (a process known as Compton scattering). The standard Compton wavelength \(\lambda\) of a neutron is given by $$\lambda=\frac{h}{m_nc} $$  
\(R_{\infty}\)  Rydberg Constant  \( 10973731.568\hspace{0.3cm}m^{−1}\) 
It can be described according to the equation:$$R_{\infty}=\frac{m_e e^4}{8\epsilon_0^2 h^3 c}$$ It is simply a parameter that describes the frequency of radiation of atomic spectra found in a Hydrogen Atom, used in the Rydberg equation of wave number: $$\frac{1}{\lambda}=R_H\left(\frac{1}{n_1^2}\frac{1}{n_2^2}\right)$$ where the electron has moved from \(n_2\) to \(n_1\) in either way.  
\(\mu_p\)  Magnetic Moment of Proton  \(1.4106067\times 10^{26}\hspace{0.3cm}J/T\) 
Every charged particle has a magnetic moment, which in case of a proton is governed by the equation: $$ \mu_p=\frac{e}{2m}L$$ where \(L\) is the angular momentum of proton.  
\(\mu_e\)  Magnetic Moment of Electron  \(9.2847643\times 10^{24}\hspace{0.3cm}J/T\) 
Every charged particle has a magnetic moment, which in case of an electron is governed by the equation: $$ \mu_p=\frac{e}{2m}L $$ where \(L\) is the angular momentum of electron.  
\(\mu_n\)  Magnetic Moment of Neutron  \(9.6623647\times 10^{27}\hspace{0.3cm}J/T\) 
Every charged particle has a magnetic moment, which in case of a neutron is governed by the equation: $$\mu_p=\frac{e}{2m}L$$ where \(L\) is the angular momentum of neutron.  
\(\mu_{\mu}\)  Magnetic Moment of Muon  \(4.490448\times 10^{26}\hspace{0.3cm}J/T\) 
Every charged particle has a magnetic moment, which in case of a muon is governed by the equation: $$\mu_p=\frac{e}{2m}L $$ where \(L\) is the angular momentum of muon.  
\(m_{\tau}\)  Mass of a tau  \(3.167477\times 10^{−27}\hspace{0.3cm} kg\) 
The mass of a static tau, also called the invariant mass.  
PhysicoChem  
\(u\)  Atomic Mass Unit  \(\1.660538\times10^(21)\hspace gm) 
The dalton or unified atomic mass unit is a nonSI unit of mass widely used in physics and chemistry. It is defined as \(\frac{1}{12}\) of the mass of an unbound neutral atom of C12 in its nuclear and electronic ground state and at rest. The atomic mass constant, denoted mu, is defined identically, giving (\mu = \frac{m(12C)}{12} = 1 Da\)  
\(F\)  Faraday Constant  \(96485.332\hspace{0.3cm} C\cdot mol^{−1}\) 
The constant is the electric charge of one mole of any Elementary charge, given by the equation: $$F=N_A e$$  
\(N_A\)  Avogadro Constant  \(6.0221\times 10^{23}\hspace{0.3cm} mol^{−1}\) 
It is the number of constituent particles in one mole of a substance.  
\(k_B\)  Boltzmann Constant  \(1.380649\times 10^{−23} \hspace{0.3cm}J\cdot K^{−1}\) 
It relates the energy of any atom to its absolute Temperature through the equation: $$ E=\frac {1}{2} f k_B T $$ where \(f\) is the degree of freedom of that atom.  
\(V_m\)  Molar Volume of Ideal Gas at STP  \(0.022710953\) 
It is the volume an ideal gas occupies at Normal Atmospheric Pressure and Temperature \((0° C)\).  
\(R\)  Molar Gas Constant  \(8.3144626\hspace{0.3cm}J\cdot mol^{−1}\cdot K^{1}\) 
The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per amount of substance. The constant is also a combination of the constants from Boyle's law, Charles's law, Avogadro's law, and GayLussac's law. It is a physical constant that is featured in many fundamental equations in the physical sciences, such as the ideal gas law, the Arrhenius equation, and the Nernst equation. Can be furthur written in the form of: $$R=N_A k_B$$  
\(c_1\)  First Radiation Constant  \(3.741771×10^{−16} \hspace{0.3cm}\text{W}\cdot \text{m}^2\) 
Derived from Planck's law, the constant is the value \(c_1=2\pi hc^2\). It is a constant used in the law.  
\(c_2\)  Second Radiation Constant  \(1.43877×10^{−2}\hspace{0.3cm} \text{m}\cdot \text{K}\) 
Another constant used in the Planck's radiation law, it is value of \(c_2=\frac{hc}{k_B}\).  
\(\sigma\)  StefanBoltzmann Constant  \(5.6703744\times 10^{−8}\hspace{0.3cm} \text{W}\cdot \text{m}^{−2}\cdot \text{K}^{−4}\) 
The constant relates the power emitted from a substance to its absolute Temperature to the power 4, as given by the StefanBoltzmann equation: $$P=\sigma \epsilon A T^4 $$ where \(\sigma\) is the aforementioned constant and \(\epsilon\) is the emissitivity of the substance. It can be further formulated as: $$ \sigma=\frac{2 \pi^5 k^4}{15 c^2 h^3}$$  
Adopted Values  
\(g\)  Acceleration due to Gravity  \(9.8\hspace{0.3cm}\text{m}\cdot \text{s}^2\) 
When a body falls freely owing to gravity, it accelerates at this rate towards the ground. Derived from the equation: $$g=\frac{GM}{R^2} $$ where \(G=6.673\times 10^{11}N\hspace{0.3cm} \cdot m^2 kg^{2}\) is the Universal Gravitational Constant \(M=6.02\times 10^{24}\hspace{0.3cm} \text{kg}\) is the mass of the Earth and \(R=6371\hspace{0.3cm} \text{km}\) is the radius of Earth.  
\(atm\)  Standard Atmospheric Pressure  \(101325\hspace{0.3cm} \text{Pa}\) 
It is the ambient pressure at standard conditions.  
\(R_K90\)  conventional value of von Klitzing constant  \(25812.807\hspace{0.3cm} \Omega\) 
\(K_J90\)  conventional value of Josephson constant  \(4.835979\times 10^{14}\hspace{0.3cm}Hz\cdot V^{1}\) 
Other  
t  Kelvin Scale at \(0°\) Celsius  \(273.15\hspace{0.3cm}\text{K}\) 
From the Kelvin Scale, the Celsius Scale is at \(273.15\hspace{0.3cm}\) units backward which means: \(\degree C+273.15=K\) 