Question

find the resistivity of wire of length 1 m and radius 2.5 mm and the wire resistance is 63 ohm.​

Answer 1

Answer:

Length of the wire = 1 m

Radius of the wire = 2.5 mm = 2.5 × 10⁻³ m

Resistance of the wire = 63 ohm

R = ρ × (l/A) ...ohm

$R = ρ \frac{l}{A} = ρ \frac{l}{\pi {r}^{2} } \\ 63 = ρ \times ( \frac{1}{\pi \times {(2.5 \times {10}^{ - 3}) }^{2} } ) \\ 63 = ρ \times ( \frac{1}{3.14 \times 6.25 \times {10}^{ - 6} } ) \\ ρ = 63 \times 3.14 \times 6.25 \times {10}^{ - 6} \\ = 1236.375 \times {10}^{ - 6} ohm \: m$

Thus, the resistivity of the wire is 1236.375 × 10^-6 ohm-m.