Chapter 29, Problem 80EAP

a. Derive an expression for the magnetic field strength at distance d from the center of a straight wire of finite length l that carries current l.

b. Determine the field strength at the center of a current carrying square loop having sides of length $\text{2}R$ .

c. Compare your answer to part b to the field at the center of a circular loop of diameter $\text{2}R$ . Do so by computing the ratio $B_{sqaure}/B_{circle}$.