Question

Resistance of a metal wire of length 1m is 26ohm at 20°c if the diameter of the wire is o.3mm. what will be the resistivity of the metal at that temperature.

Answer 1

resistance = 26 ohm
length = 1 m diameter = 0.3mm=0.0003m
radius =0.00015. area=
$\pi (r {}^{2} )$
$3.14 \times (0.00015) ^{2}$
$7 \times 10 ^{ - 8} m {}^{2}$
p = r A/l
p = 26 × (7 ×10^-8)/1
p = 0.0000018378 ohm metre