EXAMPLE Electrons emitted from the nucleus in beta decay typically have kinetic energies of approximately $1$ MeV $.$ Assume that an electron is trapped in the nucleus and then escapes via beta decay. Using the diameter of a typical nucleus to be $1\mathrm{.}0{10}^{-14}m,$ make use of the uncertainty principle to show that an electron trapped in the nucleus is unlikely to have a kinetic energy of $1$ MeV $.$