Question

In the first step of the proton–proton cycle, what is formed when two protons combine, and what is released?

Options

• Deuterium is formed, releasing a positron and a neutrino

• Tritium is formed, releasing a proton and a neutron

• Helium-3 is formed, releasing gamma radiation

• Helium-4 is formed, releasing two protons

Answer 1

In the first step of the proton–proton cycle, two protons combine to form deuterium, releasing a positron and a neutrino. This deuterium then participates in the second step of the cycle.