E=mc² is Albert Einstein's equation from his theory of relativity, showing that energy (E) and mass (m) are equivalent and interchangeable, with the speed of light squared (c²) as the conversion factor. This means that a small amount of mass can be converted into a large amount of energy, explaining phenomena like nuclear reactions and the energy produced by the sun. #science #physics #einstein #alevel #alevelphysics #alevelrevision #physicsrevision | vt.physics