Really struggling with this question guys, any help/advice will be greatly appreciated. Thanks in advance! 1. The problem statement, all variables and given/known data Sketch dispersion relations for, (i) a proton (ii) a free electron (iii) an electron, in a crystalline solid. Comment on the similarities between (ii) and (iii). 2. Relevant equations 3. The attempt at a solution I can't find any information on this topic at all! There isn't even a mention of dispersion relations in my course notes and can't find anything on the net. I have Electrical Properties Of Materials, Seventh Edition but can't find anything in there either.