Q. A photon creates a pair of electron positron with equal kinetic energy. Let kinetic energy of each particle is 0.29$\ MeV$. Then what should be energy of the photon?
A) 1.60$\ MeV$
B) 1.63$\ MeV$
C) 2.0$\ MeV$
D) 1.90$\ MeV$
Explanation
(a) The energy required to produce a pair of electron $–$positron is $1.02\ MeV$
Now, the kinetic energy of electron$-$positron pair
$\ \ \ \ \ \ \ \ \ \ \ = \ 2\ \ \times \ 0.29\ MeV\ = \ 0.58\ MeV$
Hence, the energy of photon
$\ \ \ \ \ \ \ = (1.02\ + \ 0.58)\ MeV = 1.60\ MeV$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.