Question

Two wires, one of copper and the other of manganin have same resistance and equal thickness. Which wire is longer and why?

Answer 1

Since menganese wire is thicker than copper wire so the resistance of manganese wire is more than copper wire if both the resistance are same then we know that length is directly proportional to resistance so copper wire have longer length then Mn in order to equals the resistance of maganese and copper.

Answer 2

Mangnese wire should be thicker to compensate for it's higher resistivity . Answer: Manganin is an alloy of Cu with manganese and nickel. Since the latter two metals have resistivity greater than copper, the pure copper has lower resistivity and the manganin thus has to be thicker to have the same resistance.