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shanna339
Oct 28, 2010, 05:50 PM
A sample of radioactive isotope with an original mass of 10.0 grams is observed for 24 days. After that time, 1.25 grams of the isotope remains. What is its half-life?"

Unknown008
Oct 28, 2010, 11:03 PM
Use the formula:

N = N_o \(\frac12 \)^{\frac{t}{t_{1/2}}}

DrBob1
Oct 29, 2010, 08:11 PM
Just divide 10 grams by 2 until only 1.25 grams are left. How many steps did that take? How many hours or days did each step take? There is your half life.