A carbon-14 nucleus decays to a nitrogen-14 nucleus by beta decay. How much energy (in MeV) is released if carbon-14 has a mass of 14.003242 u and nitrogen-14 has a mass of 14.003074 u?
A)0.00157 MeV
B)0.0157 MeV
C)0.157 MeV
D)1.57 MeV
E)15.7 MeV

Question

Quizplus · Accepted Answer

The energy released in a nuclear reaction can be calculated using the mass defect and Einstein's equation E=mc². The mass defect is the difference in mass between the initial and final nuclei: 14.003242 u - 14.003074 u = 0.000168 u. Converting this mass defect to energy using 1 u = 931.5 MeV/c² gives 0.000168 u * 931.5 MeV/u = 0.1567 MeV, which rounds to 0.157 MeV.

A Carbon-14 Nucleus Decays to a Nitrogen-14 Nucleus by Beta