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13.Nuclei
hard
The decay constant of a radio active substance is $0.173\, (years)^{-1}.$ Therefore :
A
Nearly $63\%$ of the radioactive substance will decay in $(1/0.173)\, year.$
B
half life of the radio active substance is $(1/0.173) \,year.$
C
one -forth of the radioactive substance will be left after nearly $8$ years.
D
$(A)$ and $(C)$ both
Solution
Given $\lambda=0.173$
$T_{1 / 2}=\frac{\ln 2}{\lambda}=\frac{0.693}{0.173} \cong 4$
Also for t $1 / 0.173$ year
Remaining nuclei $N=N_{0} e^{-1}=0.37 N_{0}$
Decay nuclie $=N_{0}-N=0.63 N_{0}$
Standard 12
Physics
