In a lab experiment, the decay of a radioactive isotope is being observed. At the beginning of the first day of the experiment the mass of the substance was 1000 grams and mass was decreasing by 9% per day. Determine the mass of the radioactive sample at the beginning of the 12th day of the experiment. Round to the nearest tenth (if necessary).Answer: □ grams
Q. In a lab experiment, the decay of a radioactive isotope is being observed. At the beginning of the first day of the experiment the mass of the substance was 1000 grams and mass was decreasing by 9% per day. Determine the mass of the radioactive sample at the beginning of the 12th day of the experiment. Round to the nearest tenth (if necessary).Answer: □ grams
Identify initial mass and decrease: Identify the initial mass and the daily percentage decrease. The initial mass of the radioactive substance is 1000 grams, and it decreases by 9% each day.
Determine decay factor: Determine the decay factor.Since the mass decreases by 9% each day, the decay factor is 1−0.09=0.91.
Calculate mass at 12th day: Calculate the mass at the beginning of the 12th day.We use the formula for exponential decay: P(t)=P0×(decay factor)t, where P(t) is the mass at time t, P0 is the initial mass, and t is the number of days.
Substitute values into formula: Substitute the values into the formula. P(11)=1000×0.9111, because we are looking for the mass at the beginning of the 12th day, which is after 11 complete days.
Perform calculation: Perform the calculation.P(11)=1000×0.9111P(11)≈1000×0.31381059609 (using a calculator)P(11)≈313.8 grams
Round to nearest tenth: Round to the nearest tenth.The mass of the radioactive sample at the beginning of the 12th day is approximately 313.8 grams when rounded to the nearest tenth.
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