Question

Two wires one of manganin and the other of copper have equal length and equal resistance. Which one of these wires will be thicker?

Answer 1

Resistance \(R=\frac{pl}{A}=\frac{pl}{\pi r^2}\)

Resistivity ρ of manganin is much greater than that of copper, therefore to keep same resistance for same length of wire, the manganin wire must be thicker.