76) (a) ΔE = 3.9 x 1026 J/s 3.00 x 108 m/s
ΔE = Δmc2
Δm = ΔE/c2
Δm = 3.9 x 1026 J/s/(3.00 x 108 m/s)2 = 4.3 x 109 kg/s
(b) The mass loss results from the fusion reaction producing more stable nuclei from less stable nuclei.