A 50.0 mg sample of an unknown radioactive substance was placed in storage and its mass...
A 50.0 mg sample of an unknown radioactive substance was placed in storage and its mass measured periodically. After 70.9 days70.9 days, the amount of radioactive substance had decreased to 3.13 mg.
What is the half-life of the unknown radioactive substance?
half-life:
days
Homework Answers
as w eknow from disintegration formula
ln ( N/No) = - Lt
L = ln ( 3.13/ 50) / 70.9
L = 0.03908 /day
expression for half life
t(1/2) = ln (2)/ L
t(1/2) = 17.735 days
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