Calculating Radioactivity: 4000 cpm to bq

Then you'll know how to convert.In summary, the initial activity of a radioactive material with a half-life of 5 days is 4000 counts/min. After 10 days, the activity would be 1000 counts/min. For an initial quantity of 200g, after 15 days, the amount left would be 25g. To convert 4000 counts/min into bq, you would need to look up the definition of bq in your book.
  • #1
dagg3r
67
0
a radioactive with a half-life of 5 days, has an initial activity of 4000 counts/min

determine the activity after 10 days

well because 1 half life is 5 days, so 10 days must be 2
so 4000/(2^2)
=1000 counts/min is that right?

2. If the initial quantitiy of radioactive material is 200gms determine the amount left after 15 days have elapsed
no of half lives = 3
200/(2^3)
=25 gms is that right?

3. convert 4000 counts per min into bq's
how do i do that?
 
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  • #2
Originally posted by dagg3r
a radioactive with a half-life of 5 days, has an initial activity of 4000 counts/min

determine the activity after 10 days

well because 1 half life is 5 days, so 10 days must be 2
so 4000/(2^2)
=1000 counts/min is that right?

Yes.

2. If the initial quantitiy of radioactive material is 200gms determine the amount left after 15 days have elapsed
no of half lives = 3
200/(2^3)
=25 gms is that right?

Yes.

3. convert 4000 counts per min into bq's
how do i do that?

You do it by looking up the definition of a bq in your book.
 
  • #3


1. Yes, your calculation for the activity after 10 days is correct. The activity would decrease by half after each half-life, so after 2 half-lives (10 days), the activity would be 1000 counts/min.

2. Your calculation for the amount of material left after 15 days is also correct. Each half-life, the amount of material would decrease by half, so after 3 half-lives (15 days), the amount left would be 25 gms.

3. To convert from counts per min to bq, you would need to know the conversion factor for the specific radioactive material you are working with. This conversion factor is based on the specific activity of the material and is typically given in bq per count. Without this information, it is not possible to accurately convert counts per min to bq.
 

1. What is the conversion factor for cpm to Bq?

The conversion factor for cpm (counts per minute) to Bq (becquerel) depends on the type of radiation being measured. For example, for alpha radiation, the conversion factor is 37 Bq/cpm, while for beta radiation, the conversion factor is 1 Bq/cpm.

2. How do you calculate Bq from cpm?

To calculate Bq from cpm, you need to know the conversion factor for the type of radiation being measured. Then, simply multiply the cpm value by the conversion factor. For example, if you have 4000 cpm of alpha radiation, the calculation would be 4000 cpm x 37 Bq/cpm = 148,000 Bq.

3. Why do we measure radioactivity in Bq instead of cpm?

Bq (becquerel) is the SI unit for measuring radioactivity, while cpm (counts per minute) is an older unit that is not used as frequently anymore. Bq provides a more precise and standardized measurement of radioactivity, as it is based on the number of radioactive decays per second.

4. Is 4000 cpm a high level of radioactivity?

The level of radioactivity considered high varies depending on the type of radiation being measured and the context in which it is being measured. In general, 4000 cpm may be considered high for alpha radiation, but low for beta or gamma radiation. It is important to consult safety guidelines and regulations for specific industries or situations.

5. How accurate is the conversion from cpm to Bq?

The accuracy of the conversion from cpm to Bq depends on the accuracy of the conversion factor and the accuracy of the cpm measurement. It is important to use reliable and calibrated equipment for accurate measurements and to double-check calculations to ensure accuracy.

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