An electron and its antiparticle are annihilated after collision. How much energy will be obtained? What will be the wavelength of the emitted radiation (energy)? (Mass of electron , speed of light  and Planck’s constant )


Correct option is

0.024 Å

The annihilation equation is  


   (electron)        (positron)          

The mass annihilation in this process is


According to energy-mass relation, the energy released is 




             = 1.02 MeV. 

Tow -photon are produced in this process, hence energy of each photon is




The wavelength corresponding to it is  




           = 0.024 Å.



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