Constants

This page lists various constants used in physics and some useful conversions.

Physical constants

The number in brackets represents the uncertainty in the constant, so that Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 6.626070040(81) \times 10^{-34}} has an uncertainty of $0.00000000081\times 10^{-34}$.

Name	Symbol	Value	Meaning	Used in	Exact
Planck's constant	$h$	$6.626070040(81)\times 10^{-34}\,$ J s	It relates the frequency of a photon to its energy	Quantum mechanics	Inexact
Speed of light	$c$	299,792,458 m s-1	This is the speed of light in a vacuum	Most of physics, such as optics and relativity	Exact
Permittivity of free space	$\epsilon _{0}$	$8.854187817...\times 10^{-12}$ F m-1	Related to the strength of an electric field produced by a charge	Electromagnetism	Exact
Permeability of free space	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \mu_0}	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 4 \pi \times 10^{-7}}	Related to the strength of [[magnetic field]s produced by a current	Electromagnetism	Exact
Elementary charge	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle e}	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 1.6021766208(98) \times 10^{-19}} C	The magnitude of the electric charge on an electron	Determines the strength of electric and magnetic fields produced by protons, electrons etc	Inexact
Avogadro's number	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle N_A}	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 6.022140857(74) \times 10^{23}} mol-1	The number of constituents in 1 mole of something	Chemistry, statistical mechanics, thermodynamics	Inexact
Ideal gas constant	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle R}	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 8.3144598(48)} J mol-1 K-1	Relates the pressure, volume, temperature and number of moles of an ideal gas	Thermodynamics	Inexact
Faraday Constant	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle F}	Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 96485 C/mol^-1}	The electric charge on one mole of electrons (Avogadro's number times elementary charge)	Chemistry, physics	Inexact

Useful Conversions

1 atm = 101.1 kPa

1.000 calorie = 4.184 Joules

1 Calorie = 1000 calories

760 torr = 1 atm

760 mm Hg = 1 atm

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Atomic mass unit: 1.00 amu = 1.67 x Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 10^{-27}} kg

Standard Temperature and Pressure (STP): temperature = 273 K and pressure = 1.00 atm

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Bond Strengths

	Mass	Charge
Proton	1.67 x Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 10^-27 } kg	+1
Neutron	1.67 x Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 10^-27 } kg	0
Electron	9.11 x Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 10^-31 } kg	-1