Question

25. Activity of radioactive element decreased to one
third of original activity i. in 9 years. After further
9 years, its activity will be
$1)i$
$2) \frac{2}{3} i$
$3) \frac{i}{9}$
$4) \frac{i}{6}$



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Answer 1

Explanation:

it's reactivity will be (3) 1/9

bcz it has same logic of half life one

Answer 2

Answer:

option (3)  $\frac{i}{9}$