formula.expert

Constants library

1 value, each with its units, its uncertainty, and where it came from.

Universal & Atomic 1

Thomson cross section measured

σe=6.6524587051×10−29 m2\sigma_{\mathrm{e}} = 6.6524587051 \times 10^{-29}\ \text{m}^{2}

m²The low-energy scattering cross section of a photon on a free electron, 6.652 458 705 × 10⁻²⁹ m² — that is 0.665 barn.