NEET Physics Nuclei Questions Solved


The rest mass of an electron as well as that of positron is 0.51 MeV. When an electron and positron are annihilate, they produce gamma-rays of wavelength(s)

(a) 0.012 Å               (b) 0.024 Å
(c) 0.012 Å to       (d) 0.024 Å to 

(a) Since electron and positron annihilate
λ=hcETotal=6.6×10-34×3×108(0.51+0.51)×106×1.6×10-19=1.21×10-12m=0.012A0

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