The isotope   512B having a mass 12.014 u undergoes  β-decay to  612C.  612C Has an excited state of the nucleus  612C*  at 4.041 MeV above its ground state. If   512B decays to  612C*, the maximum kinetic energy of the β  particle in units of MeV is (1 u=931.5 MeV/C2, where c is the speed of light in vacuum).