1. The problem statement, all variables and given/known data A 45-m long wire is coiled so that it makes a coil containing 100 circular loops, one on top of the other. If the wire carries a current of 13 A, what is the magnetic dipole moment of the coil? 21 A·m2 6.7 A·m2 3.3 A·m2 2.6 A·m2 1.2 A·m2 2. Relevant equations B(z) = u0/2pi x u/z^3 Where u0 is the permeability constant and u is the magnetic dipole moment 3. The attempt at a solution I can get as far as B(z) = (2 x 10^7 u)/z^3 I know I need to find u. It doesn't seem to mention where exactly z is, thus can't work out magnetic field. Do you think there is enough information provided in this question to solve it? Thanks.