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The activity of a freshly prepared radioactive sample is `10^(10)` disintegrations per second , whose mean life is `10^(9)s` The mass of an atom of this radioisotope is `10^(-25) kg ` The mass (in mg) of the radioactive sample is |
Answer» Correct Answer - 1 `N=N_0 e^(-lambda t)` `(dN)/(dt)=10^(10)=N_0(lambda)e^(-10^(-9)t)` At `(t=0)` `10^(10)=N_(0) 10^(-9)` Mass of sample `=N_0 =10^(-25)` =`N_0` (mass of the atom) `=10^(-6) kg` `=10^(-6) xx 10^(3) g` `=10^(-3) g` `=1 mg` . |
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