document.write( "Question 1070350: What is the Half life of carbon if it takes 11,400 years to decay to 25% of its original mass?
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What is the Half life of carbon if it takes 11,400 years to decay to 25% of its original mass?
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\n" ); document.write( "Let initial amt = 1
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\n" ); document.write( ".75 = the amt after 11400 yrs
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\n" ); document.write( "let h = the half life of the substance
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\n" ); document.write( "1*2^(-11400/h) = .25
\n" ); document.write( " $\"-11400%2Fh\"$ *ln(2) = ln(.25)
\n" ); document.write( " $\"-11400%2Fh\"$ = $\"ln%282%29%2Fln%28.25%29\"$
\n" ); document.write( " $\"-11400%2Fh\"$ = -.5
\n" ); document.write( "h = 11400 * .5
\n" ); document.write( "h = 5700 years is the half life \n" ); document.write( "

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