Question

Class X Sciences
[papers from previous years]

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

length of wire=1m
diameter of wire=0.2mm=0.0002m
Resistance of wire=10Ω
resistivity of wire= Resistancex area
                             length
area of wire=πr²=3.14×0.00000004=0.0000001256
resistivity=10x0.0000001256=0.000001256Ωm