CPB Budapest 2017

Radioactive Decay: Exponential Law

Multiplying both sides of the equation by the decay constant λ and considering equation, results to the following equation for the activity λ− λ= λ⇒λ− = )t exp( N )t(N )t exp( N )t(N

0

0

)t(N )t(A λ=

Considering the following equation for the activity results:

=

λ−

exp( A )t(A 0

)t

)t exp( N )t(N λ− = 0

Both these equations present the exponential law of radioactive decay , which states that the number of nuclei that have not decayed in the sample as well as the activity of the sample, both decrease exponentially with time .