Erg (unit)

The title of this article is ambiguous. Further meanings are listed under Erg .

Physical unit
Unit name	erg
Unit symbol	${\displaystyle \mathrm {erg} }$
Physical quantity (s)	Energy (e.g. work , internal energy , heat )
Formula symbol	${\displaystyle E;\,W;\,U;\,Q}$
dimension	${\displaystyle {\mathsf {M\;L^{2}\;T^{-2}}}}$
system	CGS system of units
In SI units	${\displaystyle \mathrm {1\,erg=0{,}1\;\mu J} }$ ${\displaystyle \mathrm {=1\cdot 10^{-7}\;{\frac {kg\,m^{2}}{s^{2}}}} }$
In CGS units	${\displaystyle \mathrm {1\,erg=1\;{\frac {cm^{2}\,g}{s^{2}}}} }$
Derived from	dyn , centimeters

The erg ( unit symbol : erg; from Greek ἔργον , ergon , work ) is a unit of measurement in the CGS system of units for energy . The unit is widely used in astrophysics and sometimes mechanics .

Except for a power of ten, the erg corresponds to the unit joule , which is common in the MBS- based International System of Units (SI) :

${\displaystyle {\begin{aligned}1\ \mathrm {erg} &=\mathrm {0{,}1\ \mu J=1\cdot 10^{-7}J} \\\Leftrightarrow 10^{7}\ \mathrm {erg} &=1\ \mathrm {J} \end{aligned}}}$

Considering the dimensions of the energy provides a dimension

energy	= Force x length
	= Mass · acceleration · length
	= Mass (length / time) 2

and therefore the unit in the cgs system

${\displaystyle {\begin{aligned}1\ \mathrm {erg} &=\mathrm {1\ g\cdot \left({\frac {cm}{s}}\right)^{2}} \\&=\mathrm {1\ dyn\cdot \ cm} \end{aligned}}}$

with the Dyn .

In Germany, the Erg is no longer a legal unit since January 1, 1978 .

See also

• Lumerg