The minimum frequency of a γ−ray that causes a deuteron to disintegrate into a proton and a neutron is md=2.0141  amu,  mp=1.0078 amu, mn=1.0087  amu

(2)Total mass of the product = 2.0165 amu which is greater than the mass of deuteron by 0.0024 amu. The extra mass must be provided by the energy of the photon. So the minimum possible frequency must be given byv=0.0024 × amu  ×  c2h=0.0024 ×1.66 × 10−27 × 3 × 1082 6.625 × 10−34Hz 1 amu =1.66 × 10−27kg=5.4 × 1020 Hz