Nuclear Physics And Radioactivity Question 55
The rest mass of an electron as well as that of positron is 0.511 MeV. When an electron and positron annihilate, they produce gamma-rays of wavelength(s) [UPSEAT 2002]
Options:
A) 0.012 Å
B) 0.024 Å
C) 0.012 Å to 0.012 nm
D) 0.024 Å to nm
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Answer:
Correct Answer: A
Solution:
Since electron and positron annihilate $ \lambda =\frac{hc}{E_{Total}}=\frac{6.6\times {{10}^{-34}}\times 3\times 10^{8}}{(0.51+0.51)\times 10^{6}\times 1.6\times {{10}^{-19}}} $ $ =1.21\times {{10}^{-12}}m=0.012{\AA} $ .
BETA
