Question

resistance of a metal wire of length 1m is 26 ohm at 20 degree Celsius. If the diameter of wire is 0.3 millimetre, what will be the resistivity of the metal at that temperature?

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

Answer 2

Answer:

Given : l = 1 m

A = πr^2

r=0.3 =0.15 mm

2

R (resistance)= pxl

A

AxR=p

l

=1.83

hope it helps