Show that for the diamond structure the Fourier component U-G of the crystal potential seen by an electron is equal to zero for G=2A, where A is a basis vector in the reciprocal lattice reffered to the conventional cubic cell

An investigator needs a uniform 30 mt field, which she intends to produce with a solenoid. she takes a long 10-cm-diameter tube and wraps wire along the length of it, wrapping 1200 turns of wire along a 75-cm length of the tube. how much current must she pass through the wire to produce the desired field?