##  [Graham's Law of Effusion](/grahams-law-effusion) 

  ##  [Graham's Law of Effusion](https://engineering.quantumdictionary.io/grahams-law-effusion-0) 

  

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**Engineering & Applied Technologies Dictionary**

 







 

 

 

 



 

 

 

 

Definition

An empirical limiting relation for ideal gases stating that, under conditions where intermolecular collisions are negligible at the orifice (effusion regime), the rate of effusion or the flux through a small aperture into a vacuum is inversely proportional to the square root of the gas's molar mass: rate ∝ 1/√M.