Radium 226 Ra , spontaneously decays to radon with the emission of an particle and a
ray. If the speed of the
particle upon emission from an initially stationary radium nucleus is 1.5 ×107 m/s, what is the recoil speed of the resultant radon nucleus? Assume the momentum of
ray is negligible compared to that of
particle.
None of these
Conservation of linear momentum requires :
with helium identified as the alpha particle. The nuclear masses can be approximated by
their mass numbers (222 and 4). Thus, the recoil speed of the radon is