1. The problem statement, all variables and given/known data When a wire carries an AC current with a known frequency you can use a Rogowski coil to determine the amplitude Imax of the current without disconnecting the wire to shunt the current in a meter. The Rogowski coil, shown in the ﬁgure, simply clips around the wire. It consists of a toroidal conductor wrapped around a circular return cord. The toroid has n turns per unit length and a cross-sectional area A. The current to be measured is given by I(t) = Imax sin (ω t). (a) Show that the amplitude, E, of the emf induced in the Rogowski coil is E = μ0 n A ω Imax. (b) Explain why the wire carrying the unknown current need not be at the center of the Rogowski coil, and why the coil will not respond to nearby currents that it does not enclose. *The figure is simply a ring of wire that has another wire wrapped around it, with a current going through the ring. 2. Relevant equations Emf= -N(dI/dt) where I = magnetic flux, not current Emf = I/R = R*(dQ/dt) where I = current Magnetic flux = *integral* (B*dA) Emf = *surface integral* (E*dL) = -(d*magnetic flux*/dt) 3. The attempt at a solution I am not really sure where to start - maybe by using the Emf= I/R ?? Can anyone help get me started in the right direction? Thanks!