Atoms And Nuclei Question 401
Question: Assume that a neutron breaks into a proton and an electron. The energy released during this process is: (mass of neutron $ =1.6725\times {{10}^{-27}}kg, $ mass of proton $ =1.6725\times {{10}^{-27}}kg, $ mass of electron $ =9\times {{10}^{-31}}kg $ ).
Options:
A) $ 0.51MeV $
B) $ 7.10MeV $
C) $ 6.30MeV $
D) $ 5.4MeV $
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Answer:
Correct Answer: A
Solution:
- $ _{0}^{1}n \rightarrow _{1}^{1}H+ _{-1}e^{0}+ \bar{v} + Q $
The mass defect during the process $ \Delta m=m_{n}-m_{H}-m_{e}=1.6725\times {{10}^{-27}} $
$ -(1.6725\times {{10}^{-27}}+9\times {{10}^{-31}}kg) $
$ =-9\times {{10}^{-31}}kg $
The energy released during the process $ E=\Delta mc^{2} $
$ E=9\times {{10}^{-31}}\times 9\times 10^{16}=81\times {{10}^{-15}} $ Joules
$ E=\frac{81\times {{10}^{-15}}}{1.6\times {{10}^{-19}}}=0.511MeV $
