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Grade upto college level Modern Physics

Nuclei of a radioactive element A are being produced at a constant rate α. The element has a decay constant λ. At time t = 0, there are N0 nuclei of the element

Profile image of Amit Saxena
12 Years agoGrade upto college level
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1 Answer

Profile image of Navjyot Kalra
12 Years ago
Hello Student,
Please find the answer to your question
(a) Let at time ‘t’ number of radioactive are N.
Net rate of formation of nuclei of A.
dN /dt = α – λ N or dN / α – λN = dt
or \int_{N_0}^{N}\frac{dN}{\alpha - \lambda N } = \int_{0}^{t} dt
Solving this equation, we get
N = 1 / λ [α – (α – λN0)e-λt] …..(1)
(b) Substituting α = 2λN0 and
t = t1/2 = 1n(2) / λ in equation (1),
we get, N = 3/2 N
(ii) Substituting α = 2λ N0 and t ⟶ ∞ in equation (1), we get
N = α / λ = 2 N0
Thanks
Navjot Kalra
askIITians Faculty