Answer :
The half life of the substance is 6.92 days.
What is the Half life ?
Half life can be defined as the time required to reduce the concentration to half of its initial value.
Here the equation given is
[tex]\rm N = N_o e^{-kt}[/tex]
The concentration will reduce to half therefore
[tex]\rm N= \dfrac{N_o}{2}[/tex]
so,
[tex]\rm 39/2 = 39 e^{- 0.1001 * t_{1/2}}[/tex]
ln 0.5 = - 0.1001 * t(1/2)
-0.693 = -.1001 * t(1/2)
t(1/2) = 6.92 days.
Therefore the half life of the substance is 6.92 days.
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