*Physical constants

*Physical constants

CONSTANT	SYMBOL	VALUE IN SI UNITS	DIMENSIONS
Absolute zero	K	-273.15 K	[K]
Astronomical unit	AU	1.5 x 10 11 m	[L ]
Atomic mass unit or unified mass	u	1.66 x 10 – 27 kg	[M ]
Avogadro’s constant	N0	6.023 x 10 23 moleucles/mol	[mol– 1]
Bohr magneton	mB	1.41 x 10 – 26  J/T	[AL2]
Bohr’s radius	b	5.29 x 10 – 11  m	[L]
Boltzmann’s constant	k	1.38 x 10 – 23 J mol – 1 K-1	[ML 2 T – 2 K – 1]
Coulomb’s constant	k	9.00 x 10 9 N m 2 C – 2	[M1 A–  2 L 3 T – 4]
Elementary charge	e	1.6 x 10 – 19  C	[AT]
Gravity	g	9.8 ms – 2	[LT – 2]
Gravitational constant	G	6.673 x 10 – 11 Nm 2 kg – 2	[M – 1 L 3 T – 2]
Mass of earth	M	5.98 x 10 24 kg	[M ]
Mass of electron at rest	m	9.1 x 10 – 31 kg	[M ]
Mechanical heat equivalent	J	4.186 J cal – 1	no dimensions
Molar volume of ideal gas at STP	Vm	2.27 x 10 – 2  m 3/mol	[L3 mol – 1]
Loschmidt constant	N0	2.69 x 10 25 m – 3	[L – 3]
Permittivity constant	e0	8.85 x 10 – 12  F/m	[M – 1 A 2 L – 3 T 4]
Permeability constant	m0	1.26 x 10 – 6  H/m	[M A– 2 L T – 2]
Planck’s constant	H	6.626 x 10 – 34 Js	[ML 2 T – 1]
Radius of earth	R	6.4 x 10 8 m	[L ]
Rydberg constant	R	1.10 x 10 – 7 m – 1	[L – 1]
Specific charge of electron	e/m	1.76 x 10 11  C/kg	[ATL – 1]
Speed of light in vacuum	c	3.0 x 10 8 m/s	[L T – 1]
Standard atmospheric pressure	1 atm	1.013 x 10 5 Nm – 2	[ML – 1 T – 2]
Solar constant	S	1.4 x 103 Wm – 2	[MT – 3]
Stefan – Boltzmann constant	s	5.67 x 10 – 8 Wm – 2 K 4	[MT – 2 K – 4]
Triple point of water	Ttr	273.16 K	[K]
Universal gas constant	R	8.31 J mol – 1 K – 1	[ML 2 T – 2 K – 1]
Wien’s displacement constant	b	2.89 x 10 – 3 mK	[LK]