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Help with A2 Nuclear Physics Question ?

Use following information:

Tellurium-128 is a Beta Emitter, with the longest half life known, measured at 2.2x10^24 years.

5) The Number of atoms of tellurium-128 in a 1g sample is:

6) The Activity of a 1g sample of tellurium-128 is

I have converted the half life to seconds and worked out the decay constant but after that I don't know what I'm doing, I've looked at my textbook and it doesn't help. I really don't know what to do :frown: I think I know how to work out 6 but I need the answer for 5.

Please help I'm stuck, Thanks for your time :smile:
Sorry you've not had any responses about this. :frown: Are you sure you've posted in the right place? :smile: Here's a link to our subject forum which should help get you more responses if you post there. :redface:


Just quoting in Fox Corner so she can move the thread if needed :wizard:

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Original post by Cinna21
Use following information:

Tellurium-128 is a Beta Emitter, with the longest half life known, measured at 2.2x10^24 years.

5) The Number of atoms of tellurium-128 in a 1g sample is:

For 5, i would do n = m/Mr to work out the moles, which would be 1/128.
Then use n * Na to get the specific number of atoms, which would be 6.022 * 10^23 * (1/128) = 4.70 * 10^21 atoms.
Not sure if this is right tbh, we haven't started nuclear physics yet but I'm using stuff from thermal physics.
Original post by Cinna21
Use following information:

Tellurium-128 is a Beta Emitter, with the longest half life known, measured at 2.2x10^24 years.

5) The Number of atoms of tellurium-128 in a 1g sample is:

6) The Activity of a 1g sample of tellurium-128 is

I have converted the half life to seconds and worked out the decay constant but after that I don't know what I'm doing, I've looked at my textbook and it doesn't help. I really don't know what to do :frown: I think I know how to work out 6 but I need the answer for 5.

Please help I'm stuck, Thanks for your time :smile:


Nuclear activity A is directly proportional to the number of parent nuclei N present at that instant:

A=λN A = \lambda N

λ \lambda depends on half-life.
(edited 7 years ago)

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