When an electron collides with a positron, the two particles annihilate each other, resulting in the production of gamma rays.

Electrons and positrons are both subatomic particles that possess opposite electric charges. When they come into contact, they undergo a process known as electron-positron annihilation, where their annihilation releases energy in the form of gamma rays.

The energy released during this annihilation is given by the equation:

where $E$ is the energy, $m$ is the combined mass of the electron and positron, and $c$ is the speed of light. Since electrons and positrons have equal mass, the total energy released in their annihilation is always the same.

Gamma rays are high-energy photons capable of penetrating various materials and are widely utilized in medical imaging and cancer treatment. In addition to gamma rays, electron-positron annihilation can also produce other subatomic particles, such as muons and pions.

The study of electron-positron annihilation is significant in particle physics, as it offers insights into the properties and behaviors of subatomic particles. Furthermore, this process represents a potential source of energy, since the energy released during annihilation could theoretically be harnessed for power generation. However, the feasibility of utilizing this energy source is still under investigation.