Answer
0.96 eV
Work Step by Step
The wavelength of the photon that is emitted has an energy equal to the band gap.
$$E_g=hf=\frac{hc}{\lambda}$$
$$=\frac{(6.63\times10^{-34}J \cdot s)(3.00\times10^8m/s)}{(1.60\times10^{-19}J/eV)(1.3\times10^{-6}m)}$$
$$=0.96 eV$$
