A sample of 100g (intially) of pure Bismuth-210 contains only 14.4 g of the radioactive substance after 14 days. Determine the mass m(t) of bismuth-210 after t days and the half-life of bismuth-210.

Any help will be much appreciated! thanx

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- Feb 24th 2009, 12:51 PMzangestu888Differntial Problem Radioactive decay
A sample of 100g (intially) of pure Bismuth-210 contains only 14.4 g of the radioactive substance after 14 days. Determine the mass m(t) of bismuth-210 after t days and the half-life of bismuth-210.

Any help will be much appreciated! thanx - Feb 24th 2009, 01:49 PMskeeter
$\displaystyle y = y_0e^{kt}

$

general equation is $\displaystyle y = 100e^{kt}$

$\displaystyle 14.4 = 100e^{k \cdot 14}$

solve for k.

use the equation and the value of k found above ...

$\displaystyle 50 = 100e^{kt}$

and solve for t to find the half-life