InterviewSolution
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InterviewSolution
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Two radioactive nuclei `P` and `Q`, in a given sample decay into a stable nucleus `R`. At time `t = 0`, number of `P` species are `4 N_0` and that of `Q` are `N_0`. Half-life of `P` (for conversation to `R`) is `1mm` whereas that of `Q` is `2 min`. Initially there are no nuclei of `R` present in the sample. When number of nuclei of `P` and `Q` are equal, the number of nuclei of `R` present in the sample would be :A. `3 N_0`B. `(9 N_0)/(2)`C. `(5 N_0)/(2)`D. `2 N_0` |
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Answer» Correct Answer - B (b) Initially `p rarr 4 N_0` `Q rarr N_0` Half-life `T_p rarr 1 min` `T_Q rarr 2 min` Let after time `t` number of nuclei of `P` and `Q` are equal, i.e., `(4 N_0)/(2^(t//1)) = (N_0)/(2^(t//2))` `4 = 2^(t//2)` `2^2 = 2^(t//2) rArr (t)/(2) = 2` `t = 4 min` Deactivate nucleus or nuclei of `R` =`(4 N_0 - (4 N_0)/(2^4)) + (N_0 - (N_0)/(2^2))` =`4 N_0 (N_0)/(4) + N_0 - (N_0)/(4) = 5 N_0 - (N_0)/(2) = (9)/(2) N_0`. |
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