College Physics
posted by Angie .
A gamma ray (a highenergy photon of light) can produce a particle antiparticle pair, each particle with mass 8.68 MeV/c2 when it enters the electric field of a heavy nucleus: γ ! λ+ + λ− .
What minimum γray energy is required to accomplish this task?
I have searched but can't come up with a numerical answer in MeV units. Please Help

You know the mass created: 2*8.68Mev/c^2
so energy= masscreated*c^2=2*8.68Mev 
thank you very, i did the calculations and it was simple math after your explanation..
i got answer as 17.36 MeV
=]