SarahM975
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Homework Equations
I was given all this information... I cannot figure it out whatsoever. I would post my attempts but there were too many. Any ideas would be helpful. I know the answer is 5.09 as the half life
Decay Constant of Copper 66
Sources do not emit radiation at a constant rate but fade away with time.
In this experiment, you monitor the count rate of a sample of copper 66 which has just been prepared.
The detector counts for one minute at each interval.
time(minutes) counts
0 ------------932
1 -------------813
2 -------------710
3 -------------619
4------------ 540
5------------ 453
6 ------------435
-
time(minutes) counts
7 ---------359
8 -----------318
9 ---------266
10 ----------239
11 ----------205
12 ------------182
13 ------------161
time(minutes) counts
14 ------------138
15 ------------121
16 --------------108
17 ------------92
18-------------- 80
19 ------------70
20 ------------61
The data in the table should satisfy the relation:
N=N0e-(lambda)t
where, N0 = the number of counts at time 0
N = the number of counts after an elapsed time T
lambda = the decay constant for the specific isotope
t = the elapsed time
Plot the count rate vs the time on semilog paper using the data found in the table. Calculate the slope.
Hint#1: Make sure you calculate the slope in the right units and that the sign of the answer make sense.
Hint#2: From the formula above the value of the slope will be "-lambda"
Be sure to enter the answer in the summary table in your lab outline.
The half-life, T, is defined as the time for the count rate to drop by a factor of 2.
(1/2)N0 = N0e^-(lambda)T
T = 0.693/lambda
Homework Statement
i cannot find the half life/slope
Homework Equations
equations above
The Attempt at a Solution
my attempts were not posted because it would make this uber long