Under external shear stress, and edge dislocation moves in a grain of copper until it is stopped along its entire length by some type of barrier. A second dislocation of the same sign lies on the same plane moves towards the pinned dislocation. If the applied shear stress is $1$ MPa and no other factors are considered, what will be the final equilibrium distance between the two dislocations? Given Data: Copper G $=42$ GPa; b $=0\mathrm{.}256$ nm and $=0\mathrm{.}35$