- #1

danielatha4

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## Homework Statement

A proton (1.6726×10-27 kg) and a neutron (1.6749×10-27 kg) at rest combine to form a deuteron, the nucleus of deuterium or "heavy hydrogen". In this process, a gamma ray (high-energy photon) is emitted, and its energy is measured to be 2.39 MeV (2.39×106 eV). Keeping all five significant figures, what is the mass of the deuteron? (Assume you can neglect the small kinetic energy of the recoiling deuteron.)

## Homework Equations

Rest Energy = m c^2

E

_{before}=E

_{after}

## The Attempt at a Solution

I found the energy before the combining by

c^2 (1.6726×10-27+1.6749×10-27) = 3.0086*10^-10 J

this should equal the energy of the deuteron (mc^2) + the energy of the photon

energy of the photon in joules: 3.8292*10^-13 J

therefore:

3.0086*10^-10 = m

_{d}c^2 + 3.8292*10^-13

m

_{d}=3.3433*10^-27 kg

However, this isn't right