In an acceleration experiment on high energy collision of electrons with position , a certain event is interpreted as annihilation of an electron position pair of total energy $10.2\;Bev$ into two $\gamma$ rays of equal energy. What is the wave length associated with each $\gamma$- ray $(1Bev= 10^9\;ev)$ ?

Question

$\begin{array}{1 1} 2.436 \times 10^{-16} m \\ 2.436 \times 10^{-16} cm \\ 2.436 \times 10^{16} m \\ 2.436 \times 10^{16} m \end{array}$