The Attractive Force Between Protons and Neutrons in the Nucleus

Multiple Choice

The attractive force between protons and neutrons in the nucleus is brought about by the exchange of a virtual pi-meson (mπ = 140 MeV/c²) .Estimate the longest time a π can exist in accordance with the uncertainty principle ΔE⋅Δt = h/2π.(h/2π = 1.05 × 10−³⁴ J⋅s,1 eV = 1.6 × 10−¹⁹ C)

A) 3.3 × 10−¹⁸ s
B) 2.4 × 10−²¹ s
C) 4.7 × 10−²⁴ s
D) 6.9 × 10−²⁷ s