Question

The decay constant of a radioactive nuclide is 9.5x10^-3 s^-1 . At given instant, the activity of a specimen of the nuclide is 80 mCi. The time interval required for the activity to decline to 40 mCi is closest to: ?

Answer 1

This time is the half-life.

N(t)/N(0) = exp(-0.0095 t)

ln(0.5) = - 0.0095 t

solve for t

Answer 2

73 ?