PHYSICS RESOURCES DATABASE

PHYSICAL CONSTANTS

 

 

The value of physical quantities have been written in a format so that the number can be copied and pasted into a spreadsheet for calculations. For example, 6.022x1023 ® 6.022E23 and 1.381x10-23 ® 1.381E-23.

QUANTITY

SYMBOL

VALUE

UNIT

Avagadro's number

NA

6.022E23

mol-1

Bohr radius

ao or r1

5.292E-11

m

Bohr magneton

m B

9.274E-24

J.T-1

Boltzmann constant

k or kB

1.381E-23

8.617E-5

J.K-1

eV.K-1

Coulomb force constant

k or ko

1/4p e o

8.988E9

N.m2.C-2

Electron charge

e

1.602E-19

C

Electron charge/mass ratio

e/me

1.759E11

C.kg-1

Electron Compton wavelength

l C

2.426E-12

m

Electron magnetic moment

m e

9.285E-24

J.T-1

Electron mass

me

9.109E-31

kg

Electron rest energy

mec2

0.511

MeV

Faraday constant

F

9.649E4

C.mol-1

Gravitation constant

G

6.673E-11

N.m2.kg-2

Neutron mass

mN

1.674929E-27

1.00866

kg

u

Neutron magnetic moment

m N

9.662E-27

J.T-1

Neutron rest energy

mNc2

939.566

MeV

Permeability of free space

m o

1.257E-6

T.m.A-1

Permeability constant

Bio-Savart constant

m o/4p

k'

1.000E-7

T.m.A-1

Permittivity of free space

e o

8.854E-12

C2.N-1.m-2

Planck's constant

h

6.626E-34

4.136E-15

J.s

eV.s

Planck's constant (hbar)

h

1.055E-34

6.582E-16

J.s

eV.s

Proton magnetic moment

m P

1.411E-26

J.T-1

Proton mass

mP

1.672623E-27

1.007276

kg

u

Proton rest energy

mPc2

938.272

MeV

Rydberg constant

R

1.097E7

m-1

Speed - light

c

2.99792458E8

m.s-1

Speed - sound (air @ 20C)

 

343

m.s-1

Stefan Boltzmann constant

s

5.671E-8

W.m-2.K-4

Universal gas constant

R

8.315

J.mol-1.K-1

Wien's displacement constant

 

2.898E-3

m.K