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A freshly prepared sample of a radioisotope of half - life `1386 s ` has activity `10^(3) ` disintegrations per second Given that `ln 2 = 0.693` the fraction of the initial number of nuclei (expressed in nearest integer percentage ) that will decay in the first `80 s ` after preparation of the sample is |
Answer» Correct Answer - 4 We know `(0.693)/(t_(1//2)) = (2.303)/(t) log ((N_(0))/(N))` Given `t_(1//2) = 1386` sec t = 80 sec, `N_(0) = 1` N = remaining fraction after 80 sec `(0.693)/(1386) = (2.303)/(80) log ((1)/(N))` On solving N = 0.96 Fration decayed = 1 - 0.96 = 0.04 precentage decay `= 0.04 xx 100 = 4` |
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