In a Certain $\gamma$ Decay Process, an Excited Neon Atom Emits A

Multiple Choice

In a certain $\gamma$ decay process, an excited neon atom emits a $\gamma$ -ray that has an energy of 1.630 MeV. The neon atom in the ground state has a mass of 19.992 435 u. What is the mass of the excited neon atom?

A) 17.498 658 u
B) 18.746 422 u
C) 19.994 185 u
D) 19.999 685 u
E) 20.003 185 u