Saved Bookmarks
| 1. |
Estimate the number of mean lives clasped , when the number of atoms in a radioactive sample decrease to 5% of the original value. |
|
Answer» Solution : Let the required number of mean lives elapsed be .m., then `t = m lt TAU GT = m/lamda` and `N = 5% ` of `N_0 = 1/(20)N_0` But `N=N_0e^(-lamdat)` `:. N_(0)/(20) = N_(0)e^(-m)` or `e^(m) = 20 ` or , m = LN 20 = ln 2 + ln 10 = 0.693 + 2.303 `~~3` `:.` At the of about three average lives, the number of atoms (undecayed) would fail to 5% . |
|