If aluminium has a resistivity of 2.5×10 –8 Ω m, what will be the resistance of an aluminium wire with a length of 1 m and a cross-sectional area of 2 mm2 and what is the conductivity of the...

If aluminium has a resistivity of 2.5×10^–8
Ω m, what will be the resistance of an aluminium wire with a length of 1 m and a cross-sectional area of 2 mm2 and what is the conductivity of the aluminium?

What length of copper wire, of diameter 1.5 mm, is needed to give a resistance of 0.3 Ω if the resistivity is 1.7×10^–8
Ω m?