Einstein's E=mc² — FAQ
Frequently asked questions about Einstein's E=mc² (E=mc²).
Q1. What does c represent in E=mc²?
c is the speed of light: approximately 299,792,458 metres per second. Squaring it gives an enormous multiplier (~9×10¹⁶), which is why even tiny masses contain colossal energy.
Q2. Where is E=mc² applied in real life?
Nuclear power plants, atomic weapons, PET scan machines (medical imaging), and the fusion reactions powering the Sun all convert mass directly into energy.
Q3. Can we actually convert mass to energy completely?
Matter-antimatter annihilation achieves 100% conversion. Nuclear fission and fusion convert only a small fraction (~0.1%) of mass, but that fraction is already enormous.
Have more questions? Try the interactive calculator at /tools/einsteins-emc2-visualizer