Annihilation of electron and positron

[ehabmozart]

Homework Statement

A positron with kinetic energy 2.2MeV collides with an electron at rest, and annihilate each other.
a. Calculate the average energy of the two gamma photons produced as a result of annihilation

Homework Equations

The Attempt at a Solution

I would infact calculate the energy in the left hand side including the rest masses.. isn't it.. So it would be (0.511 x 2) + 2.2 = 3.222 MeV .. But this doesn't seem the answer.. Any help guys?

 

[tiny-tim]

hi ehabmozart!

A positron with kinetic energy 2.2MeV collides with an electron at rest, and annihilate each other.
a. Calculate the average energy of the two gamma photons produced as a result of annihilation
…
I would infact calculate the energy in the left hand side including the rest masses.. isn't it.. So it would be (0.511 x 2) + 2.2 = 3.222 MeV .. But this doesn't seem the answer.. Any help guys?

maybe they want you to divide by 2, for the average?

 

[ehabmozart]

Thanks.. I guess this gave me the answer... Dude, i will owe u if u just solve the question in this link.. Drivin' me crazy and no replies till now
Here is the link "https://www.physicsforums.com/showthread.php?t=612956"