Difference between revisions of "Constants"

Latest revision as of 02:00, July 17, 2019

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 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 0.00000000081 \times 10^{-34}} .

Name	Symbol	Value	Meaning	Used in	Exact
Planck's 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 h}	$6.626070040(81)\times 10^{-34}\,\mathrm {J} \,\mathrm {s}$	It relates the frequency of a photon to its energy	Quantum mechanics	Inexact^[1]
Speed of light	$c$	$299,792,458\,\mathrm {m} \,\mathrm {s^{-1}}$	This is the speed of light in a vacuum	Most of physics, such as optics and relativity	Exact^[2]
Permittivity of free space	$\epsilon _{0}$	$8.854187817...\times 10^{-12}\,\mathrm {F} \,\mathrm {m^{-1}}$	Related to the strength of an electric field produced by a charge	Electromagnetism	Exact^[3]
Permeability of free space	$\mu _{0}$	$4\pi \times 10^{-7}\,\mathrm {H} \,\mathrm {m^{-1}}$	Related to the strength of magnetic fields produced by a current	Electromagnetism	Exact^[4]
Elementary charge	$e$	$1.6021766208(98)\times 10^{-19}\,\mathrm {C}$	The magnitude of the electric charge on an electron	Determines the strength of electric and magnetic fields produced by protons, electrons etc.	Inexact^[5]
Avogadro's number	$N_{A}$	$6.022140857(74)\times 10^{23}\,\mathrm {mol^{-1}}$	The number of constituents in 1 mole of something	Chemistry, statistical mechanics, thermodynamics	Inexact^[6]
Ideal gas constant	$R$	$8.3144598(48)\,\mathrm {J} \,\mathrm {mol^{-1}} \,\mathrm {K^{-1}}$	Relates the pressure, volume, temperature and number of moles of an ideal gas	Thermodynamics	Inexact^[7]
Faraday Constant	$F$	$96485\mathrm {C} \,\mathrm {mol^{-1}}$	The electric charge on one mole of electrons (Avogadro's number times elementary charge)	Chemistry, physics	Inexact^[8]
Gravitational constant	$G$	$6.67408(31)\times 10^{-11}\,\mathrm {N} \,\mathrm {m^{2}} \,\mathrm {kg^{-2}}$	Constant related to the strength of Newtonian gravity	Newtonian gravity	Inexact^[9]
Boltzmann constant	$k$	$1.38064852(79)\times 10^{-23}\,\mathrm {J} \,\mathrm {K^{-1}}$	Thermodynamics		Inexact^[10]
Reduced Planck's constant	$\hbar$	$1.054571800(13)\times 10^{-34}\,\mathrm {J} \,\mathrm {s}$	Quantum mechanics	It is Planck's constant divided by $2\pi$ .	Inexact^[11]
Wien displacement constant	$b$	$2.8977729(17)\times 10^{-3}\,\mathrm {m} \,\mathrm {K}$	Relates the temperature of a black body to the peak in its spectrum		Inexact^[12]
Standard acceleration due to gravity	$g$	$9.80665\,\mathrm {m} \,\mathrm {s^{-2}}$	This is the acceleration of any object near to the earth's surface when gravity is the only force acting (i.e., no air resistance).	Mechanics	Exact^[13]
Proton mass	$m_{p}$	$1.672621898(21)\times 10^{-27}\,\mathrm {kg}$	Rest mass of a proton		Inexact^[14]
Neutron mass	$m_{n}$	$1.674927471(21)\times 10^{-27}\,\mathrm {kg}$	Rest mass of a neutron		Inexact^[15]
Electron mass	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 m_e}	$9.10938356(11)\times 10^{-31}\,\mathrm {kg}$	Rest mass of an electron		Inexact^[16]

Useful Conversions

Length

1 metre = 39.37 inches 1 metre = 3.281 feet 1 kilometre = 0.6213 miles

1 mile = 5280 feet 1 mile = 1760 yards

Weight

1 kilogram = 35.27 ounce 1 kilogram = 2.205 pounds

Pressure

1 atm = 101.1 kPa 1 atm = 760 torr 1 atm = 760 mm Hg

Other

Atomic mass unit: 1.00 amu = 1.67 x 10⁻²⁷ kg

1.000 calorie = 4.184 Joules

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

Relative mass and charge of subatomic particles found in atoms.

Atomic particles
	Relative Mass	Relative Charge
Proton	1	+1
Neutron	1	0
Electron	1/1837	-1

Prefixes

Prefixes in front of a unit indicate that that unit should be multiplied by a multiple of ten, e.g. Giga is 10⁹, so 1 GPa = 10⁹ Pa.

Name	Symbol	Power
Pico	p	10⁻¹²
nano	n	10⁻⁹
micro	μ	10⁻⁶
milli	m	10⁻³
centi	c	10⁻²
deci	d	10⁻¹
deca	da	10¹
hecto	h	10²
kilo	k	10³
mega	M	10⁶
giga	G	10⁹
tera	T	10¹²

References

[1] ttp://physics.nist.gov/cgi-bin/cuu/Value?h

[2] ttp://physics.nist.gov/cgi-bin/cuu/Value?c

[3] ttp://physics.nist.gov/cgi-bin/cuu/Value?ep0

[4] ttp://physics.nist.gov/cgi-bin/cuu/Value?mu0

[5] ttp://physics.nist.gov/cgi-bin/cuu/Value?e

[6] ttp://physics.nist.gov/cgi-bin/cuu/Value?na

[7] ttp://physics.nist.gov/cgi-bin/cuu/Value?r

[8] ttp://ch302.cm.utexas.edu/echem/echem-stoich/echem-stoich-all.php

[9] ttp://physics.nist.gov/cgi-bin/cuu/Value?bg

[10] ttp://physics.nist.gov/cgi-bin/cuu/Value?k

[11] ttp://physics.nist.gov/cgi-bin/cuu/Value?hbar

[12] ttp://physics.nist.gov/cgi-bin/cuu/Value?bwien

[13] ttp://physics.nist.gov/cgi-bin/cuu/Value?gn

[14] ttp://physics.nist.gov/cgi-bin/cuu/Value?mp

[15] ttp://physics.nist.gov/cgi-bin/cuu/Value?mn

[16] ttp://physics.nist.gov/cgi-bin/cuu/Value?me

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@@ Line 1: / Line 1: @@
-This page lists various constants used in [[physics]] and some useful conversions.
+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 <math>6.626070040(81) \times 10^{-34}</math> has an uncertainty of <math>0.00000000081 \times 10^{-34}</math>.
 {| class="wikitable" style="background: white"
@@ Line 38: / Line 37: @@
 |<math>\mu_0</math>
 |<math>4 \pi \times 10^{-7} \, \mathrm{H} \, \mathrm{m^{-1}}</math>
-|Related to the strength of [[magnetic field]s produced by a [[current]]
+|Related to the strength of [[magnetic field]]s produced by a [[current]]
 |[[Electromagnetism]]
 |Exact<ref>http://physics.nist.gov/cgi-bin/cuu/Value?mu0</ref>
@@ Line 46: / Line 45: @@
 |<math>1.6021766208(98) \times 10^{-19} \, \mathrm{C}</math>
 |The magnitude of the electric charge on an electron
-|Determines the strength of electric and magnetic fields produced by [[proton]]s, [[electron]]s etc
+|Determines the strength of electric and magnetic fields produced by [[proton]]s, [[electron]]s etc.
 |Inexact<ref>http://physics.nist.gov/cgi-bin/cuu/Value?e</ref>
 |-
@@ Line 101: / Line 100: @@
 |<math>g</math>
 |<math>9.80665 \, \mathrm{m} \, \mathrm{s^{-2}}</math>
-|This is the [[acceleration]] of any object near to the earth's surface when [[gravity]] is the only force acting (ie, no air resistance).
+|This is the [[acceleration]] of any object near to the earth's surface when [[gravity]] is the only force acting (i.e., no air resistance).
 |[[Mechanics]]
 |Exact<ref>http://physics.nist.gov/cgi-bin/cuu/Value?gn</ref>
@@ Line 129: / Line 128: @@
 ==Useful Conversions==
-atm = 101.1 kPa
+===Length===
+metre = 39.37 inches
+metre = 3.281 feet
+kilometre = 0.6213 miles
+mile = 5280 feet
+mile = 1760 yards
-.000 calorie = 4.184 Joules
+===Weight===
-Calorie = 1000 calories
+kilogram = 35.27 ounce
+kilogram = 2.205 pounds
-torr = 1 atm
+===Pressure===
+atm = 101.1 kPa
+atm = 760 torr
+atm = 760&nbsp;mm Hg
-&nbsp;mm Hg = 1 atm
+===Other===
---------
+Atomic mass unit: 1.00 amu = 1.67 x 10<sup>−27</sup> kg
-Atomic mass unit: 1.00 amu = 1.67 x <math>10^{-27}</math>kg
+.000 calorie = 4.184 Joules
 Standard Temperature and Pressure (STP): temperature = 273 K and pressure = 1.00 atm
----------
+----
+Relative [[mass (science)|mass]] and [[charge]] of subatomic particles found in [[atom]]s.
 {| class="wikitable" style="text-align:left"
-|+ Bond Strengths
+|+ Atomic particles
 |-
-!  !! Mass !! Charge
+!  !! Relative Mass !! Relative Charge
 |-
-| '''Proton''' || 1.67 x <math>10^-27 </math> kg || +1
+| '''Proton''' || 1 || +1
 |-
-| '''Neutron''' || 1.67 x <math>10^-27 </math> kg || 0
+| '''Neutron''' || 1 || 0
 |-
-| '''Electron''' || 9.11 x <math>10^-31 </math> kg|| -1
+| '''Electron''' || 1/1837 || -1
 |-
 |}
+==Prefixes==
+Prefixes in front of a unit indicate that that unit should be multiplied by a multiple of ten, e.g. Giga is 10<sup>9</sup>, so 1 GPa = 10<sup>9</sup> Pa.
+{| class="wikitable"
+|-
+!Name
+!Symbol
+!Power
+|-
+|Pico
+|p
+|10<sup>−12</sup>
+|-
+|nano
+|n
+|10<sup>−9</sup>
+|-
+|micro
+|μ
+|10<sup>−6</sup>
+|-
+|milli
+|m
+|10<sup>−3</sup>
+|-
+|centi
+|c
+|10<sup>−2</sup>
+|-
+|deci
+|d
+|10<sup>−1</sup>
+|-
+|deca
+|da
+|10<sup>1</sup>
+|-
+|hecto
+|h
+|10<sup>2</sup>
+|-
+|kilo
+|k
+|10<sup>3</sup>
+|-
+|mega
+|M
+|10<sup>6</sup>
+|-
+|giga
+|G
+|10<sup>9</sup>
+|-
+|tera
+|T
+|10<sup>12</sup>
+|}
 ==References==
 {{reflist}}