Question

The resistance of a wire of 0.01cm radius is 10Ω. If resistivity of the material of wire is 50 x 10-8Ωm, find the length of the wire

Answer 1

Radius = 0.01 cm = 10^-4 m
Area = πr² = 3.14 × 10^-8
Resistivity = 50 × 10^-8 Ohm-m
Resistance = 10 ohm

Length = Resistance × Area/ Resistivity
$l \: = \frac{10 \times 3.14 \times {10}^{ - 8} }{50 \times {10 }^{ - 8} } \: m = 62.36 \: cm$