Answer
$\lambda = 1.24\times 10^{-15}~m$
Work Step by Step
We can find the wavelength of the photon:
$\lambda = \frac{hc}{E}$
$\lambda = \frac{(6.63\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{(1.00\times 10^9~eV)(1.6\times 10^{-19}~J/eV)}$
$\lambda = 1.24\times 10^{-15}~m$
