Asked by mat

a copper wire with a diameter of 1.5mm is joined to an aluminium wire which has a diameter of 2.3mm.the wire carries a current of 12A.what is the current density in each wire
Answered by Steve
As I recall, current density is I/a, where I is the current, and a is the cross-sectional area. So, that makes it

12/(π/4 d^2) A/mm^2

where d is 1.5 or 2.3
Answered by mat
I can just use one of them
Answered by Chanz
One will be limiting