Answer : The correct option is, First-order reaction.
Explanation :
First order reaction : A reaction is said to be of first order if the rate is depend on the concentration of the reactants, that means the rate depends linearly on one reactant concentration.
If the reaction is first order, then
\(Rate=-\frac{d[A]}{dt}=k[A]^1=k[A]\)
In the radioactive decay, the number of radioactive atoms are decaying per unit time is proportional to the total number of atoms present at that time.
The formula becomes :
\(-\frac{d[N]}{dt}=k[N]^1=k[N]\)
From this we conclude that the decay rate is proportional to the first power of radioactive atoms present. So, the radioactive decay reactions always follow the first order kinetics or reaction.
Hence, the correct option is, First-order reaction.
