A cardiac pacemaker is powered by a nuclear battery containing a small sample of plutonium-238, which is an alpha emitter. The source has an activity of 12 MBq12\text{ MBq}12 MBq, and each alpha particle is emitted with a kinetic energy of 5.5 MeV5.5\text{ MeV}5.5 MeV.
What is the rate of thermal energy released by this source?
8.8×10−13 W8.8 \times 10^{-13}\text{ W}8.8×10−13 W
1.1×10−11 W1.1 \times 10^{-11}\text{ W}1.1×10−11 W
1.1×10−5 W1.1 \times 10^{-5}\text{ W}1.1×10−5 W
6.6×1013 W6.6 \times 10^{13}\text{ W}6.6×1013 W
