How to Calculate E = mc²
What is E = mc²?
Einstein's famous equation E = mc² expresses the equivalence of energy (E) and mass (m), connected by c² (speed of light squared, ~9 × 10¹⁶ m²/s²). It means a tiny amount of mass contains an enormous amount of energy — the basis of nuclear power and weapons.
Step-by-Step Guide
- 1E = mc² where c = 299,792,458 m/s (speed of light)
- 2c² = 8.9875 × 10¹⁶ J/kg
- 31 gram of mass contains 89.875 terajoules of energy
- 4That's equivalent to ~21.5 kilotons of TNT — similar to the Hiroshima bomb
Worked Examples
Input
Mass = 1 gram (0.001 kg)
Result
E = 8.99 × 10¹³ J = 89.9 TJ
Equivalent to ~21.5 kilotons TNT
Input
Mass = 1 kg
Result
E = 8.99 × 10¹⁶ J = 89.9 PJ
Equivalent to 21.5 megatons TNT
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