Question 634: Atoms & Nuclei

Question

A sample of radioactive element has a mass of 10 g at an instant t = 0. The approximate mass of this element in the sample after two mean lives is

Accepted Answer

Using the relation for mean life.
Given : t = 2t = 2$$\left( {{1 \over \lambda }} \right)$$
Then from M = M
0
e
-$$\lambda $$t
= 10e
-$$\lambda $$$$\left( {{1 \over \lambda }} \right)$$
= $$10{\left( {{1 \over e}} \right)^2}$$ = 1.35 g

Answer

1.35 g

Answer

2.50 g

Answer

3.70 g

Answer

6.30 g

Atoms & Nuclei

A sample of radioactive element has a mass of 10 g at an instant t = 0. The approximate mass of this element in the sample after two mean lives is

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