effusion
Sign in to savethumb|250px|The image on the left shows effusion, whereas the image on the right shows Molecular diffusion|diffusion. Effusion occurs through an orifice smaller than the mean free path of the particles in motion, whereas diffusion occurs through an opening in which multiple particles can flow through simultaneously.|alt=
Article
7 sectionsContents
- Etymology
- Into a vacuum
- Measures of flow rate
- Effect of molecular weight
- Graham's law
- Knudsen cell
- References
thumb|250px|The image on the left shows effusion, whereas the image on the right shows Molecular diffusion|diffusion. Effusion occurs through an orifice smaller than the mean free path of the particles in motion, whereas diffusion occurs through an opening in which multiple particles can flow through simultaneously.|alt=
In physics and chemistry, effusion is the process in which a gas escapes from a container through a hole of diameter considerably smaller than the mean free path of the molecules. Such a hole is often described as a pinhole and the escape of the gas is due to the pressure difference between the container and the exterior.