Question

calculate the resistivity of a wire of lenght 1m, radius 0.01cm and of resistance 20 ohm

Answer 1

resistance = (resistivity ) × length ÷ area------(1)
area of cross section of wire =
$\pi \times radius ^{2}$
=
$\pi \times .0001 ^{2} m ^{2}$
=3.14*.0001
314/1000000=.000314
put in formula(1)
20=resistivity*1÷.000314
resistivity =0.00628