Answer: radioactive decay
Explanation: Radioactivity is the phenomenon in which an unstable nuclei is converted to a stable nuclei by emitting radiations.
Radioactive decay always follows first order kinetics given by:
\(t=\frac{2.303}{k}\log\frac{a}{a-x}\)
where,
k = rate constant
t = time taken for decay process
a = initial amount of the reactant
a - x = amount left after decay process
Half life is the time required to decompose a radioactive material to half of its original value.
\(t_\frac{1}{2}=\frac{2.303}{k}\log\frac{a}{a-\frac{a}{2}}\)
\(t_\frac{1}{2}=\frac{2.303}{k}\times log2}\)
\(t_\frac{1}{2}=\frac{0.693}{k}\)
