Q37. Consider electrons in graphene, which is a planar monoatomic layer of carbon atoms. If the dispersion relation of the electrons is taken to be e(k) = ck (where c is constant) over the entire k -space, then the Fermi energy 6 depends on the number density of electrons p as 2 (a) 6 p? (b) 6 p (C) 6 p' (d) 6 p