A piece of wire bent into a loop, as shown in Fig. 10.5, carries a current that increase...

A piece of wire bent into a loop, as shown in Fig. 10.5, carries a current that increases linearly with time:

I ( t ) = kt (−∞ < t < ∞).

Calculate the retarded vector potential A at the center. Find the electric field at the center. Why does this (neutral) wire produce an electric field? (Why can’t you determine the magnetic field from this expression for A?)

Figure 10.5