Question

Resistance of a metal wire of length 2m is 30ohm at 20degree celcius. If the diameter of the wire is 0.5 mm , what will be the resistivity of the metal at that temperarure ?

Answer 1

we know from the extension of Ohm's law: R = ρl/A [R= 26Ω; l = 1m; diameter = 0.3mm, hence radius = 0.15mm, or, 0.15*10^(-3)m] putting this value in the relation, and finding out the value of ρ (resistivity), we have,

ρ = RA/l Therefore, ρ = Rпr²/l hence, ρ = 1.84 * 10^-6 Ωm ....Answer!