Question
The halflife of is 28 years. How much is the disintegration rate of 15 mg of this isotope? The Avogadro’s number is .




None of these
medium
Solution
1 gramatom of has a mass of 90 g and contains atoms. Therefore, the number of atoms in 1 g of , and that in 15 mg is
.
The halflife T of is 28 years. Therefore, its decay constant is
.
The rate of disintegration, when N atoms are present, is given by
.
Substituting the above values of and N, we get
.
SIMILAR QUESTIONS
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