Question

resistance of a metallic wire of length 1m is 26 ohm at 20 degree Celsius if the diameter of the wire is 0.3 mm what will be the resistivity of the metal at that temperature

Answer 1

Given:      l = 1 m

                 d = 0.3 mm

                 A = r2 = 3.14 x 2.25 x 10-8= 7.065 x 10-8m2

Formula:         = R x A / l

                            = 26 x 7.065 x 10-8

                            =183.69 x 10-8m

Thus, the resistivity of the metal wire at 20C is 183.69 x 10-8m.