document.write( "Question 301593: Use the formula N = Iekt, where N is the number of items in terms of the initial population I, at time t, and k is the growth constant equal to the percent of growth per unit of time. A certain radioactive isotope decays at a rate of 0.275% annually. Determine the half-life of this isotope, to the nearest year.
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Algebra.Com's Answer #216230 by stanbon(75887) $\"\"$ $\"About$

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Use the formula N = Iekt, where N is the number of items in terms of the initial population I, at time t, and k is the growth constant equal to the percent of growth per unit of time. A certain radioactive isotope decays at a rate of 0.275% annually. Determine the half-life
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\n" ); document.write( "N(t) = Ie^(kt)
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\n" ); document.write( "(1/2)I = I*e^(-0.275t)
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\n" ); document.write( "e^(-0.275t) = 0.5
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\n" ); document.write( "Take the natural log and solve for \"t\":
\n" ); document.write( "-0.275t = ln(0.5)
\n" ); document.write( "t = 2.52 years (half-life)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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