Initial activity has a an uncertainty of 2% Activity at a time t has an uncertainty of 10% The change in activity corresponds to the increase in uncertainty of 8% So the source must decay by 8%, giving 230 days
Interesting question. Intuitively, I'd be tempted to add 2 and 10% to get an uncertainty of 12%, but I find it hard to get my head around it. Do you know the actual answer?
Interesting question. Intuitively, I'd be tempted to add 2 and 10% to get an uncertainty of 12%, but I find it hard to get my head around it. Do you know the actual answer?
I found that A=(3.5×105±2%)e5.27×365t but I don't know how to proceed from here. How to find % error of A?
The exponent should be negative (activity is decreasing).
A=A0e−λt λ=t21ln2 Here the decay constant λ is 0.132 (to 3 sf) year-1 (using the formula given in the syllabus, where λ=t210.693, decay constant is 0.131 year^-1
There is no need to find the decay constant You may use A=A02−Tt where T is the half-life to find the time in the same units as the half life then convert to unit required in the question
The exponent should be negative (activity is decreasing).
A=A0e−λt λ=t21ln2 Here the decay constant λ is 0.132 (to 3 sf) year-1 (using the formula given in the syllabus, where λ=t210.693, decay constant is 0.131 year^-1
There is no need to find the decay constant You may use A=A02−Tt where T is the half-life to find the time in the same units as the half life then convert to unit required in the question