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 $$ = 9 \times {10^{ - 31}}kg$$ ).
A.
$$0.73\,MeV$$
B.
$$7.10\,MeV$$
C.
$$6.30\,MeV$$
D.
$$5.4\,MeV$$
Answer :
$$0.73\,MeV$$
Solution :
$$_0^1n \to _1^1H{ + _{ - 1}}{e^0} + \bar v + Q$$
The mass defect during the process
$$\eqalign{
& \Delta m = {m_n} - {m_H} - {m_e} \cr
& = 1.6725 \times {10^{ - 27}} - \left( {1.6725 \times {{10}^{ - 27}} + 9 \times {{10}^{ - 31}}kg} \right) \cr
& = - 9 \times {10^{ - 31}}kg \cr} $$
The energy released during the process
$$\eqalign{
& E = \Delta m{c^2} \cr
& E = 9 \times {10^{ - 31}} \times 9 \times {10^{16}} = 81 \times {10^{ - 15}}Joules \cr
& E = \frac{{81 \times {{10}^{ - 15}}}}{{1.6 \times {{10}^{ - 19}}}} = 0.511MeV \cr} $$
Releted MCQ Question on Modern Physics >> Atoms or Nuclear Fission and Fusion
In the nuclear fusion reaction
$$_1^2H + _1^3H \to _2^4He + n$$
given that the repulsive potential energy between the two
nuclei is $$ \sim 7.7 \times {10^{ - 14}}J,$$ the temperature at which the gases must be heated to initiate the reaction is nearly
[Boltzmann’s Constant $$k = 1.38 \times {10^{ - 23}}J/K$$ ]
The binding energy per nucleon of deuteron $$\left( {_1^2H} \right)$$ and helium nucleus $$\left( {_2^4He} \right)$$ is $$1.1\,MeV$$ and $$7\,MeV$$ respectively. If two deuteron nuclei react to form a single helium nucleus, then the energy released is