SI Units and Symbols used in the Guide

Subject

Physical Quantity

Symbol

Name

Unit

Mechanics

Mass

m, M

kilogram

kg

Linear position

Length, Distance

Radius

x, r

 l, d

R

meter

m

Time

t,

second

s

Linear angle,

Angular position

,

radian

rad

Spherical angle

steradian

sr

Area

A

-

m²

Volume

V

-

m³

Moment of inertia

I

-

kg*m²

Density

-

kg/m³

Linear velocity

v, u, c

-

m/s

Angular velocity

,

-

rad/s

Linear momentum

p

-

kg*m/s

Angular momentum

L

-

kg*m²/s

Linear acceleration

a

-

m/s²

Angular acceleration

-

rad/s²

Force

F

newton

N=kg*m/s²

Torque

-

N*m

Impulse

I

-

N*s

Work

Energy

W

E

joule

J=N*m

Power

P

watt

W=J/s

Dynamic viscosity

-

Pa*s

Electricity and Magnetism

Current

I

ampere

A

Charge

Q, q, e

coulomb

C=A*s

Current density

j

-

A/m²

Volume charge density

-

C/m³

Surface charge density

-

C/m²

Linear charge density

-

C/m

Electric potential

Voltage

emf

V

volt

V=J/C

Electric field

E

-

N/C, V/m

Electric flux

-

V*m

Electric moment

p_e

-

C*m

Resistance

R, r

ohm

=V/A

Specific resistance

-

*m

Capacitance

C

farad

F=C/V

Specific conductivity

-

(*m)^-1

Magnetic field

B

tesla

T=N/(A*m)

Magnetic flux

weber

Wb=T*m²=V*s

Inductance

Mutual-inductance

L

M

henri

H=Wb/A

Magnetic moment

p_m

-

A*m²

Polarization

P

-

C/m²

Magnetization

I

-

A/m

Thermodynamics

Temperature

T

kelvin

K

Substance quantity

M

mole

mol

Pressure

P

-

Pa

Heat

Q

-

J

Heat capacity

Entropy

C

S

-

J/K

Specific heat

c

-

J/(kg*K)

Molar heat

c_m

-

J/(mol*K)

energy flux

j

-

W/m²

Surface tension

-

N/m

Stress

Elasticity modulus

E

pascal

Pa=N/m²

Oscillations and Waves

Wavelength

-

m

Wave number

k

-

m^-1

Frequency

f

hertz

Hz

Energy density

-

J/m³

Energy flux

J

-

J/m²

Intensity

I

-

J/(m²*s)

Reactance

Impedance

X

Z

ohm

=V/A

Optics

Focal length

f

-

m

Luminous intensity

I

candela

cd

Luminous flux

lumen

lm=cd*m²

Illuminance

E

lux

lk=lm/m²

Brightness

L

-

cd/m²

Linear absorption coefficient

-

m^-1

Quantum Physics

Mass absorption coefficient

-

m²/kg

Radioactive activity

A

becquerel

Bq=s^-1

Absorbed dose

D

gray

Gy=J/kg