At a given time there are 25% undecayed nuclei in a sample. After 10 seconds number of undecayed nuclei reduces to 12-5%. Then mean life of the nuclei will be about:

At a given time there are 25% undecayed nuclei in a sample. After 10 s

1.	At a given time there are 25% undecayed nuclei in a sample. After 10 seconds number of undecayed nuclei reduces to 12-5%. Then mean life of the nuclei will be about:
Answer» 10 sec 15 sec 20 sec 22 sec Solution :`N/N_(0)=(1/2)^(t//T)` `N_(1)/N_(0)=1/4 or t_(1)=2T` `N_(2)=1/8 or t_(2)=3T` `T=t_(2)-t_(1)=10s"=HALF LIFE"` `T_("aver.")=(T)/(0.693)=14.43sec`

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At a given time there are 25% undecayed nuclei in a sample. After 10 seconds number of undecayed nuclei reduces to 12-5%. Then mean life of the nuclei will be about:

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