QUANTITY

SYMBOL

VALUE

UNIT

Avagadro's number

N_A

6.022E23

mol^-1

Bohr radius

a_o or r₁

5.292E-11

m

Bohr magneton

m _B

9.274E-24

J.T^-1

Boltzmann constant

k or k_B

1.381E-23

8.617E-5

J.K^-1

eV.K^-1

Coulomb force constant

k or k_o

1/4p e _o

8.988E9

N.m².C^-2

Electron charge

e

1.602E-19

C

Electron charge/mass ratio

e/m_e

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

m_e

9.109E-31

kg

Electron rest energy

m_ec²

0.511

MeV

Faraday constant

F

9.649E4

C.mol^-1

Gravitation constant

G

6.673E-11

N.m².kg^-2

Neutron mass

m_N

1.674929E-27

1.00866

kg

u

Neutron magnetic moment

m _N

9.662E-27

J.T^-1

Neutron rest energy

m_Nc²

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

m_P

1.672623E-27

1.007276

kg

u

Proton rest energy

m_Pc²

938.272

MeV

Rydberg constant

R

1.097E7

m^-1

Speed - light

c

2.99792458E8

m.s^-1

Speed - sound (air @ 20°C)

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