Sr-90 causes

Strontium-90 causes

Radioactive Sr-90 can enter and accumulate in human body through

Radioactive Sr-90 can enter and accumulate in human body through

Strontium-90 decays with the emission of a beta- particle to form Ytrium-90 .The reaction is represented by the equation _(38)Sr^(90) rarr _(39)Y^(90) + _(-1)e^0 + 0.55 MeV the decay constant is 0.025 year ^(-1) . Suggest,with a reason,which nucleus _(38)Sr^(90) or _(39)Y^(90) ,has the greater binding energy.

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