After absorbing a slowly moving neutron of mass mN (momentum ~ 0) a nucleus of mass M breaks into two nuclei of masses m1 and 5m1 (6m1 = M + mN), respectively. If the de Broglie wavelength of the nucleus with mass m1 is λ, the de Broglie wavelength of the other nucleus will be
λ
25 λ
5 λ
λ/5