Answer
$\lambda = 7.8\times 10^{-14}~m$
Work Step by Step
We can find the energy of the photon:
$E = 8.0~MeV+8.0~MeV$
$E = 16.0~MeV$
We can find the wavelength of the photon:
$E = \frac{hc}{\lambda}$
$\lambda = \frac{hc}{E}$
$\lambda = \frac{(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{(16.0\times 10^6~eV)(1.6\times 10^{-19}~J/eV)}$
$\lambda = 7.8\times 10^{-14}~m$
