Assuming that 0.1% of the total mass of Uranium-235 converts to energy through fission reaction:
Take the 235U mass, which is about 235 u.
Convert the mass to kilograms: m = 235 × 1.66×10⁻²⁷ kg = 3.9×10⁻²⁵ kg.
Evalue the mass that converts to energy: Δm = 0.1% × 3.9·10⁻²⁵ kg = 3.9×10⁻²⁸ kg.
Multiply it by the squared speed of light, c² = 9×10¹⁶ m²/s².
The resulting energy equals about 3.51×10⁻¹¹ J or 219 MeV.
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