Question

What does the 0.693 represent in the equation of half life (t1/2 = 9.693/k) ?

Answer 1

It is the natural logarithm of 2.

Explanation:

I don't really understand the equation you mention in your question, for that I would need more information. However, it might help you to know that `0.693` is the same as `ln(2)`. This is used for calculating half life / the exponential decay constant:

`lambda = ln2/T`

in which `T` is the half life of an element. This you can use in the half life equation.

For more information check the answer to the following question on this website: What is the half life formula?