One of the thermonuclear or fusion reactions that takes place inside a star such as our Sun is the production of helium-3
(3He, with two protons and one neutron) and a gamma ray (high-energy photon) in a collision between a proton (1H) and a
deuteron (2H, the nucleus of “heavy” hydrogen, consisting of a proton and a neutron):
The rest mass of the proton is 1.0073 u (unified atomic mass unit, 1.7 × 10−27 kg), the rest mass of the deuteron is 2.0136
u, the rest mass of the helium-3 nucleus is 3.0155 u, and the gamma ray is massless.
(a) The strong interaction has a very short range and is essentially a contact interaction. For this fusion reaction to take
place, the proton and deuteron have to come close enough together to touch. The approximate radius of a proton or
neutron is about 1 × 10−15 m. What is the approximate initial total kinetic energy of the proton and deuteron