Conductivity Formula and Equation with solved Examples

The Conductivity (σ) of a material is the reciprocal of specific resistance. Unit of conductivity is mho/meter

Formula and Equation for Conductivity

σ = 1/ρ

Conductivity can also be expressed in terms of R, l and a

σ = L/RA

where ρ = RA/l
and
R = Resistance of the conductor
A = Area of cross-section
ρ = Specific resistance or resistivity

SI unit of conductivity is mho/meter or ℧/m

Example

Find the conductivity of 2 m long conductor having resistance 20 ohms and cross-sectional area of 3 mm2

Solution:

From given data L = 2m; R = 20 ohms; A = 3 mm2 = 3 * 10-6 m2

Conductivity = (2 m) / (20 * 3 * 10-6 ) = 33.33k ℧/m

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