ex_5664_sol_Y09: Missing v=\frac{\partial E}{\partial k} in part 3. Bad presentation of part 2 ex_5664_sol_Y10: Bad Format. Question 1 is wrong (missing p in the spin-orbit term) ex_5664_sol_Y11: grammar "that generates". sec.(3) easier with v = dE/dk. ex_5664 V להשאיר בתרגול[search the forum for more comments on this exercise]