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Radioactivity, decay calculation:
•
Number of nuclei prone to decay:
N(t) = N e
-
λ
t
0
•
Activity:
A(t) = -
∆
N(t) /
∆
t ≈
N(t)
A(t) = A
0
. e
-
λ
t
•
Decay constant:
λ
= ln(2) / T
½
= 0.693 / T
½
•
Half life of the source:
A(t = T
½
) = ½ A
0