Question

 A wire is 1.0 m long, 0.2 mm in diameter and has a resistance of 10 Ω. Calculate the resistivity of its material?

 

Answer 1

 Given length of the wire, l = 1 m

Diameter of the wire, d = 0.2 mm

So the radius of the wire, r = 0.1 mm = 0.0001 m

Area of cross-section of the wire, =  `A=pir^2=3.14xx(0.0001)^2=3.14xx10^-8m^2`Resistance of the wire R=10 Ω 

So resistivity `=rho=(RA)/l` 

`rho=3.14xx1^7 `Ωm 

Thus,the resistivity of the material,`rho=3.14xx10^-7` Ωm