In an accelerator experiment on high energy collision of electrons with positrons, a certain events is interpted as annhilation of an electron-positron pair of total energy 10.2 BeV into two `gamma`-rays of equal energy. What is the wavelength associated with each `gamma`-rays? `(1BeV=10^(9)eV)`

Explanation

Total energy of 2 `gamma -rays =10.2BeV=10.2xx10^(9)eV`
`:.` Energy of each `gamma -ray, E=1/2(10.2xx10^(9)xx1.6xx10^(-19))J=8.16xx10^(-10)J`
As energy of `gamma-rays, E=hv=(hc)/lambda :. lambda=(hc)/E = (6.63xx10^(-34)xx3xx10^(8))/(8.16xx10^(-10)) =2.346xx10^(-16)m`