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soul5
Apr23-09, 11:41 PM
1. The problem statement, all variables and given/known data

Ok so I'm doing this practise problem but I have no clue what to do.

"A radioactive sample intended for irradiation of a hospital patient is prepared
at a nearby lab. The sample has a half-life of 83.61 h. What should it's initial activity be if it's activity is to be 7.0 X 10 ^ 8 Bq when it is used to irradiate the patient for 24 h?


2. Relevant equations


T 1/2 = Ln2/λ

N = N0e^λt


3. The attempt at a solution

Would you just do this?


N = 7.0 X 10 ^ 8 Bq e ^(83.61 - 24)

?

please help

phyzmatix
Apr24-09, 12:53 AM
[b]Would you just do this?


N = 7.0 X 10 ^ 8 Bq e ^(83.61 - 24)

?

please help

Unfortunately not, start with

T1/2 = ln2/lambda
lambda = ln2/(T1/2)

and try again. Hope this helps :smile: