Question

A $1MeV$ positron encounters a $1MeV$ electron travelling in opposite direction. The total energy released is (in MeV)

• A. $2$
• B. $3.02$
• C. $1.02$
• D. $2.04$

Answer 1

The correct option is B $3.02$

$e^{+}+e^{-}\to 2\gamma$
Total energy of two $\gamma$ proton $=1.02MeV$
energy of positron $=1MeV$
energy of electron $=1MeV$
Total energy lost $=1+1+1.02$
$=3.02MeV$