The resistance of a wire of 0.01 cm radius is 7 ohms. If the resistivity of the material of the wire is 44 ×…
The resistance of a wire of 0.01 cm radius is 7 ohms. If the resistivity of the material of the wire is 44 × 10−6 ohm meter, calculate the length of the wire.
Solution
r=0.01 cm= 0.01 × 10−2 m, R= 7 ohm
ρ=44 × 10−6 Ωm
A=πr2
R = ρ(l/A) → l = (R×A)/ρ
l = [7Ω×(0.01×10−2)2×(22/7) m2] / (44×10−6 Ωm)
l =0.5 × 10−2 m