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Calculate the half life and mean life of Radium -226 of activity 1Ci, Given the mass of Radium - 226 is 1 gram and 226 gram of radium consists of 6.023xx10^23 atoms. |
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Answer» Solution :ACTIVITY of 1 gram of radium is `A=3.7xx10^10` distingration PER second [i.e., `1Ci=3.7xx10^10` disintegration per second] No. of ATOMS in 1 gram of radium is `N=(6.023xx10^23)/226=2.665xx10^21` Using `A=lambdaN` `lambda=A/N=(3.7xx10^10)/(2.665xx10^21)=1.388xx10^(-11)` per second Half - life of radium is `T=0.693/lambda=0.693/(1.388xx10^(-11))` `T=0.499xx10^11` second `=4.99xx10^10` second Mean - Life , `tau=1/lambda=1/(1.388xx10^(-11))` `=0.720xx10^11` second `tau=7.20xx10^10` second. |
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