Exact enumeration enumerate the 2n microstates for the n= 4 ising chain and find the corresponding contributions to z for free boundary conditions. then show that z4 and z3 satisfy the recursion relation (5.45) for free boundary conditions.

Place several e-field sensors at a few points on different equipotential lines, and look at the relationship between the electric field and the equipotential lines. which statement is true? 1-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of higher voltages. 2-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of lower voltages. 3-at any point, the electric field is parallel to the equipotential line at that point.