The SI and CGS units of energy are joule and erg respectivel. How many ergs are equal to one joule.

Explanation

DimensioN/Ally, Energy `= msssxx(velocity)^2`
`= mass xx(length/time)^2=ML^2T^-2`.
Thus, 1joule `= (1kg)(1m)^2(1s)^-2`
and `1erg=(1g)(1cm)^2(1s)^-2`
` (1 joule)/(1erg)= ((1kg)/(1g))((1m)/1cm)^2) ((1s)/(1s)^-2)`
=((1000g)/(1g)) ((100cm)/(1cm))^2= 1000xx10000=10^2`.
So, 1 joule, `10^7` erg.