# Constants Used in Physics, Chemistry and Engineering

Some of the most important and frequently used constants in physics such as the speed of light, Plank's constant, Earth acceleration and mass, etc ... are listed below.

Definition Value
Mass of Earth m E = 5.98 � 1024 Kg
(mean) Radius of Earth r E = 6.4 � 106 m
Mass of Moon m M = 7.36 � 1022 Kg
(mean) Radius of Moon r M = 1.74 � 106 m
Mass of Sun m s = 1.99 � 1030 Kg
(mean) Radius of Sun r s = 6.96 � 108 m
Acceleration due to Earth Gravity (near surface of Earth) g = 9.8 m/s2
Speed of Light in Vacuum c = 3.00 � 108 m/s
Gravitational Constant (appears in Newton's law of universal gravitation) G = 6.67 � 10-11 N�m2 / kg2
Permeability in Vacuum μ0 = 4π � 10-7 T�m / A
Permittivity in Vacuum ε0 = 8.854 � 10-12 F / m
Coulomb's Constant (in Coulomb's Law) k = 9.00 � 109 N�m2/C2
Planck's constant h h = 6.63 � 10-34 J�s
Elementary Charge e e = 1.60 � 10-19 C
Mass of Electron me = 9.109 � 10-31 Kg
Mass of Proton mp = 1.673 � 10-27 Kg
Mass of Neutron mn = 1.675 �10-27 Kg