Question

A 10m wire has 1mm diameter and resistance of 7 ohm. Calculate the resistivity of the material.

Answer 1

Answer:

5.498 x 10^-7 Ωm

Explanation:

First convert 1mm to 0.001m.  

As diameter is 0.001m therefore radius is 0.0005m. Now find the cross-sectional area of the wire using this radius

Crossectional area= pi r square

                                = pi (0.0005)^2

                                = 7.85398 x 10^-7

Resistance= (resistivity x length) / area

therefore resistivity = (resistance x area)/length

                                 = (7 x 7.85398 x 10^-7) / 10

                                 =5.498 x 10^-7 Ωm