Fission, Fusion, and Chain Reactions
Radioactive Decay Law: Radioactive nuclei decay exponentially: $N(t) = N_0 e^{-\lambda t}$, where half-life $t_{1/2} = \frac{\ln 2}{\lambda}$. Instantaneous activity is $A = \lambda N$.
Mass Defect & Binding Energy: Nuclear mass defect $\Delta m = [Z m_p + (A-Z)m_n] - M_{\text{nucleus}}$ yields nuclear binding energy $E_b = \Delta m c^2$.
Nuclear Fission & Fusion: Fission ($^{235}\text{U} + n \to \text{Fission Fragments} + 2\text{--}3n + \sim 200\text{ MeV}$) produces self-sustaining chain reactions. Fusion ($^2\text{H} + ^3\text{H} \to ^4\text{He} + n + 17.6\text{ MeV}$) powers stars.
Operating Instructions: Switch tabs in the left sidebar to simulate Fission chain cascades, thermonuclear Fusion, and Half-life decay kinetics.