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The activity of a sample of radioactive material was measured over 12 h. The following net...

The activity of a sample of radioactive material was measured over 12 h. The following net count rates were obtained at the times indicated:

Time (h) Counting Rate (counts/min)
1 3100
2 2450
4 1480
6 910
8 545
10 330
12 200

1a + b) Wanted you to find the disintegration constant and the half-life. I've found those correctly. The disintegration constant is .24974 h^-1, and the half-life is 2.77 hours. (you had to take ln() and find the slope, etc.)

1c) Was to find the counting rate at t = 0. Which is 4*10^3 counts/min.

However, I am stuck on 1d... How do I acheive an answer of 9.59*10^6?

1d) Assuming the efficiency of the counting instrument to be 10%, calculate the number of radioactive atoms in the sample at t = 0???

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genius_generous answered 2 years ago
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