Question

Electrical conductivity of the material of a conductor of length 3m, area of cross section 0.2mm² having a resistance of 2 Ω is

Answer 1

Explanation:

let resistivity or conductivity be ß

then

R=ß.L/A

A=0.2mm² ====>m²

1m=1000mm

1m²=1000²mm²=10⁶mm²

0.2mm²=0.2×10^-6 m²or0.2/10⁶ m²

12=ß×L/A

12=ß×3/0.2/10⁶

12=ß×3×10⁶×10/2

12=ß×15×10⁶

ß=12/15×10⁶

ß=4/5×10⁶

ß=4×10^-6/5

ß=0.8×10^-6

ß=8×10^-7 or 0.8×10^-6 ohm / m²