We are asked to show that we can have a "spatially uniform E-field" in a conductor according to E=Eo*exp(-t/tau) where tau=ErEo/sigma where Er is the relative permittivity and sigma is the conductivity. I know we need to use curl(H) = ErEo*dE/dt + sigma*E and for some reason we say that curl H is equal to zero. then we get a simple ODE to solve. I'm having trouble coming up with a geometrical argument for why curl(H) = zero. any hints appreciated.