Question

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 500 grams and mass was decreasing by 8% per day. Determine the mass of the radioactive sample at the beginning of the 13th day of the experiment. Round to the nearest tenth (if necessary).

Answer 1

Using an exponential function, it is found that the mass of the radioactive sample at the beginning of the 13th day of the experiment was of 169.1 mg.

What is an exponential function?

A decaying exponential function is modeled by:

$A(t) = A(0)(1 - r)^t$

In which:

• A(0) is the initial value.

• r is the decay rate, as a decimal.

At the beginning of the first day of the experiment the mass of the substance was 500 grams and mass was decreasing by 8% per day, hence A(0) = 500, r = 0.08, and the equation is given by:

$A(t) = A(0)(1 - r)^t$

$A(t) = 500(1 - 0.08)^t$

$A(t) = 500(0.92)^t$

At the 13th day, the mass is given by:

$A(13) = 500(0.92)^{13} = 169.1$

More can be learned about exponential functions at brainly.com/question/25537936