.^(90)Sr decays to .^(90)Y by beta decay with a half-life of 28 years. .^(90)Y decaysby beta-to .^(90)Zr with a half-life of 64h. A pure sample of .^(90)Sr is allowed to decay. What is the valued of (N_(Sr))/(N_(y)) after (a) 1h (b) 10 years ?

.^(90)Sr decays to .^(90)Y by beta decay with a half-life of 28 years.

1.	.^(90)Sr decays to .^(90)Y by beta decay with a half-life of 28 years. .^(90)Y decaysby beta-to .^(90)Zr with a half-life of 64h. A pure sample of .^(90)Sr is allowed to decay. What is the valued of (N_(Sr))/(N_(y)) after (a) 1h (b) 10 years ?
Answer» Solution :`N_(sr)=N_(Sr)^(0)R^((-lambda_(sr)t))` ....(1) `N_(y)=(lambda_(sr)N_(sr)^(0))/(lambda_(y)-lambda_(sr))[E^((lambda_(sr)t))-e^((-lambda_yt))]`.......(2) Dividing the two EQUATIONS `(N_(y))/(N_(sr))(lambda_(sr))/(lambda_(y)-lambda_(sr))[1-e^((-lambdat))(lambda_(sr)-lambda_(y))t]` `lambda_(sr)=0.693//(28xx365xx24)=2.825xx10^(-6)h^(-1)` `lambda_(y)=0.693//64=0.0108 h^(-1)` (a) For `t=1h` and using the VALUES for the decay constant `N_(sr)//N_(y)=3.56xx10^(5)` (b) For `t=10 "year", N_(sr)//N_(y)=3823`

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.^(90)Sr decays to .^(90)Y by beta decay with a half-life of 28 years. .^(90)Y decaysby beta-to .^(90)Zr with a half-life of 64h. A pure sample of .^(90)Sr is allowed to decay. What is the valued of (N_(Sr))/(N_(y)) after (a) 1h (b) 10 years ?

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