a wire of unknown material has a cross sectional area 5 mm^2 and length 12cm. The wire carries current density j = 3uC/s/m^2 and has a voltage difference of 30 V held constant it ends.
A) what is the total current in the wire ?
B) what is the resistivity of the unknown material ?
C) At what rate is electromechanical energy being converted into thermal energy in this wire?