When and electron-positron pair annihilates, the energy released is about.

Options

A. `0.8 xx 10^-13 J`
B. `3.2 xx 10^-13 J`
C. `1.6 xx 10^-13 J`
D. `4.8 xx 10^-13 J`

Answer

C

Explanation

( c) Electron and positron are identical in all respect except that charges on them are opposite when an electron and a positron meet together, they completely annihilate each other and two photons are produced
`e^+ + e^- rarr 2 gamma`
The rest mass energy of each particle, electron and positron is `0.511 MeV`. Hence, `2 xx 0.511 MeV` energy of photon is converted to resy mass energy of two particles.
The energy is
`E' = 2 xx 0.511 xx 10^6 xx 1.6 xx 10^-19`
`E' = 1.6 xx 10^-13 J`.