The radius (r), length (l) and resistance (R) of a metal wire was measured in the laboratory as [2024]
r=(0.35±0.05)cm
R=(100±10)ohm
l=(15±0.2)cm
The percentage error in resistivity of the material of the wire is
(2)
∆ρρ=∆RR+2∆rr+∆ll
=10100+2×0.050.35+0.215
=110+27+175
∆ρρ=39.9%