Friday

February 27, 2015

February 27, 2015

Posted by **Anonymous** on Tuesday, May 5, 2009 at 10:06am.

- physics -
**drwls**, Tuesday, May 5, 2009 at 11:24amTwo days is 48 hours or 2.18 half-lives. The original number of radioactive nuclei, 2 days earlier, is higher by a factor 2^2.18 = 4.53, so there were N0 = 145,000 radioactive nuclei then.

There is a formula that relates activity per molecule (k) to half life (T). It is k = ln2/T = 0.693/T

T = 22 hours = 1320 min

The initial activity is

A = N0*k = (145,000)(0.693)/1320

= 76 decays/min

**Answer this Question**

**Related Questions**

physics-Radioactivity - 1) The number of radioactive nuclei in a particular ...

chemistry - The half-life for the radioactive decay of calcium-47 is 4.5 days.If...

calc - The half-life of polonium is 139 days, but your sample will not be useful...

physics - After 1.84 days, the activity of a sample of an unknown type ...

Physcis 30 - Q1) If there are 100 radioactive atoms with a half-life of 30 ...

Physics 30 - The activity of a sample of a radioactive isotope is 1800Bq. If ...

chemistry -- radioactive decay - suppose you have a 150 gram sample of ...

Radioactivity - Beryllium-7 has a half-life of 53 D. A sample was observed for ...

physics - Radioactive nuclei are produced in an irradiated sample at the rate of...

Chemistry - Which radioactive sample would contain the greatest remaining mass ...