Multiple choice general knowledge With which of the following theories is the formula E=mc 2 most closely associated? General relativity Special relativity The blackbody Effect Planck's law Reveal answer Fill a bubble to check yourself B Correct answer Explanation E=mc² emerges from special relativity (1905), relating mass and energy. General relativity (1915) deals with gravity. Blackbody radiation and Planck's law are quantum phenomena, though connected to Einstein's other work.