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._(29)^(64) Cu can decay by beta^(-) or beta^(+) emmision, or electron capture. It is known that ._(29)^(64) Cu has a half life of 12.8 hrs with 40% probability of beta^(-) decay 20% probability of beta^(+) decay and 40% probability of electron capture. The mass of ._(29)^(64) Cu is 63.92977amu whil e ._(30)^(64) Zn is 63.92914 amu and ._(28)^(64) Ni is 63.92796 amu. What is the half life for electron capture? |
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Answer» `5.12` Hrs. `._(29)^(64)Cu rightarrow ._(28)^(64)Ni+._(+1)^(0)e+VQ=(m_(Zn)-m_(Ni)-2me)C^(2)` ` ._(29)^(64)Cu+._(-0)^(0)e rightarrow ._(28)^(64)Ni+VQ=(m_(2n)-m_(Ni))C^(2)` `lambda=lambda_(1)+lambda_(2)+lambda_(3)(lambda_(1)=0.4lambda,lambda_(2)=0.2lambda,lambda_(3)=0.4lambda)` `T_(1//2) e-capture=(T_(1//2))/(0.4)=(12.8)/(0.4)=32` hrs. |
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