Correct Answer - After 10 years ⇒0.7814μg
0.2278 mugRadioactivedisintegrationsareoffirstorder.Thus,Decayconstant
.^(90)Sr(k)=(0.693)/(t_(1//2))=(0.693)/(28.1years).
=2.466xx10^(-2)year^(-1)
a.Amount≤ftafter10years
:
a=mug,t=10 years , (a-x)=?
k=2.466xx10^(-2)year^(-1)
:.k=(2.303)/(t)log
(a)/(a-x)
2.466xx10^(-2)=(2.303)/(10)log
(1mug)/((a-x))
or log(a-x)=-0.1071+1-1=bar(1).8929or(a-x)=Antilog
bar(1).8929
=0.7814 mugb.Amount≤ftafter60years:
2.466xx10^(-2)=(2.303)/(60)log (1mug)/((a-x))
log(a-x)=-0.6425
=0.2278mu g `
