Question

the resistance of a metal wire of length 1m is 26ohms . If the diameter of the wire is 0.3mm. What will be the resistivity of metal at that temperature ?

Answer 1

We are given,
R=26ohms, Length(l)= 1m , and diametre of the wire = 0.3
Let us first find the area of the cross section then,
A= π(d/2)²
=3.14(0.3/2)²
=3.14(3 * 10~⁴/2)² m²
=7.06 * 10 to the power -8..
As you know that,
R= Resitivity * length of conductor/ Area of cross section.
By putting the given values we get,
26 ohm= Resitivity * 1m/ 7.06* 10 to the power -8.
Therefore , Resitivity = 7.06 * 10 to the power -8 * 26 / 1.
= 1.8 * 10 to the power -6 ohm metre...