In an accelerator experiment on high energy collisions of electrons with positrons, a certain event is interpreted as annihilation of an electron-positron pair of total energy 10.2 Gev into two `gamma`-rays of equal energy . What is the wavelength associated with each`gamma`- rays?(1GeV =`10^(9)eV`)

Explanation

Energy of two `gamma`-rays = 10.2 GeV
`:.` Energy of each `gamma`-rays = 5.1 GeV `= 5.1 xx 10^(9) eV`
`:. lamda = (hc)/(E) = (6.626 xx 10^(-34) xx 3 xx 10^(8))/(5.1 xx 10^(9) xx 1.6 xx 10^(-19)) = 2.44 xx 10^(-16)m`