To learn to apply the concept of current density and microscopic Ohm's law.
A "gauge 8" jumper cable has a diameter d of 0.326 centimeters. The cable carries a current I of 30.0 amperes. The electric field E in the cable is 0.062 newtons per coulomb.
(a) What electric field (E') would have been required to create a current of 30.0 amperes in an aluminum wire of the same diameter? The resistivity (rho) of aluminum is 2.75 x 10^-8 ohm-meters. Express your answer in newtons per coulomb.