Linked from
The 16 pages that link to Exponential distribution, each with the reason it gives.
Random variableBroader topic: It models waiting times between events in a Poisson process.
Mean free pathRelated: In a uniform medium, free-flight distances commonly follow this distribution.
Poisson processRelated: Successive waiting times between events follow this distribution.
Method of momentsRelated: Its theoretical mean gives a direct moment equation for the rate.
Gamma distributionBroader topic: It is the gamma distribution’s shape-one special case.