List of top Mechanical Metallurgy Questions on Dislocation Energy

Which one of the following options is correct?
In a face-centered cubic metal, Shockley partial is:

Which one of the following dislocation dissociation reactions is feasible in face-centered cubic metals?

The lattice parameter of Ni (face centered cubic) is \(0.35\) nm and its shear modulus is \(76\) GPa. Find the strain energy per unit length of a screw dislocation in the Ni crystal (rounded off to two decimal places), in units of \(10^{-9}\ \text{J/m}\).