The radioactive isotope \({ }^{238} \mathrm{Pu},\) used in pacemakers, decays by
emitting an alpha particle with a half-life of 86 yr. (a) Write an equation
for the decay process.
(b) The energy of the emitted alpha particle is \(9.0 \times 10^{-13}
\mathrm{~J},\) which is the energy per decay. Assuming that all the alpha
particle energy is used to run the pacemaker, calculate the power output at
\(t=0\) and \(t=10 \mathrm{yr} .\) Initially \(1.0 \mathrm{mg}\) of \({ }^{238}
\mathrm{Pu}\) was present in the pacemaker. (Hint: After \(10 \mathrm{yr}\), the
activity of the isotope decreases by 8.0 percent. Power is measured in watts
or \(\mathrm{J} / \mathrm{s}\).