Conductors

When a potential difference of 115 V is applied between the ends of a 9.66-m-long wire, the current density is J = 1.42 A/cm2. Calculate the conductivity of the wire material.
For a hypothetical electronic device, the potential difference DV, measured across the device, is related to the current i by DV = (3.55 x 106 V/A2)i2. (a) Find the resistance when the current is 2.40 mA. (b) At what value of the current is the resistance equal to 16.0 W?
Calculate the mean free time t between collisions for conduction electrons in aluminum at 20 C using tables from the lecture. Each atom of aluminum contributes three conduction electrons. The density of aluminum is 2.7 g/cm3 and it has a molar mass of 27 g/mol.