FIITJEE stuff

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the mean lives of a radioactive substance are 1620yrs for alpha emission and 405yrs for beta emission respectively. find out the time during which three-fourth of the sample will decay if it is decaying both by alpha emission and beta emission simultaneously.

#Physics #Modern physics

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2 Answers

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Avinav Prakash ·2010-01-15 09:11:09

1/Î»1=1620 ; 1/Î»2=405 thus..Î» (net)=1620/5=324

now...amt left = 1/4

1/4=e^-Î»t=e^-324t
takin ln...
t comes "approx" as 449 years...ans i think this is the way...

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dinks007 ·2010-01-15 09:26:26

got it .....u r correctttt

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