Inside the Sun

PHYSICS · Multi-part · A Level · Physics · Nuclear physics · Nuclear physics

Problem

Inside the Sun, two protons combine in the first step of the proton–proton chain:

p+p\;\longrightarrow\;d+e^{+}+\nu_{e},

where the energy carried away by the neutrino

\nu_{e}

can be ignored for this calculation. Given atomic masses (in

u

p=1.007825

d=2.014102

e^{+}=0.000549

. Constants:

1\,u\,c^{2}=931.5\,\text{MeV}

1\,\text{MeV}=1.602\times10^{-13}\,\text{J}

. Answer the following: (i) Compute the energy released in one such reaction, in MeV. (ii) Calculate the energy obtainable (in joule) if

1.0\,\text{kg}

of pure hydrogen (protons) were to undergo this reaction completely, assuming each proton participates exactly once.