Question: What is the exact relationship between half-life and relaxation time?
I just wanted to nail down the difference/similarity between these two concepts. I did a web search, and even found a direct reference, but it was an exercise in an on-line textbook asking exactly what I am asking, and I copied and pasted that exercise question as my question above.
Now, we all know that half-life is the time it takes for the substance to decay to half its size, and relaxation time is the time it takes for the substance to decay to 1/e of its size, so why have both concepts? My guess is that it is similar to the difference between degree measure and radian measure: Half-life is useful when dealing with specific practicalities, whereas relaxation time is more convenient when discussing theory.
22.May.2011 (Beijing time)