Uncertainty in Electron Momentum and Position We want Ax =10-11 m (i.e.,0.1 A) h ApAX≥4 △P24元·△X 6.6×10-34Js △p≥ 12.6×10-11m =5.3x10-24kgms1 How big is this uncertainty? △p=m。·△vso △V= △P me 10-2kg.m.s- 1030kg =107ms1 Suppose we look for the electron again after only 1x10-14 s: △x=(10m·s)(10-14s)=10-7m=1000A!Uncertainty in Electron Momentum and Position e– ? ? We want Δx ≈ 10-11 m (i.e., 0.1 Å) ΔpΔx ≥ so Δp ≥ = 5.3x10– 24 kgms-1 How big is this uncertainty? Suppose we look for the electron again after only 1x10-14 s: h 4π h 4π • Δx Δp = me • Δv so Δv = Δp me Δv ≈ 10−23 kg• m• s−1 10−30 kg = 107 m• s−1 Δx = (107 m • s−1 )•(10−14 s) = 10−7 m = 1000Å! Δp ≥ 6.6 × 10−34J⋅ s 12.6 × 10−11m II-5