Conductivity `(kappa)` of any conducting material is defined as the

Options

A. reciprocal of resistance
B. reciprocel of resistivity
C. product of resistivity and current
D. product of resistance and current

Answer

B

Explanation

`Ohm's` law can be applied to the electrolytic as well as metallic conductor. It related the resistance `'R'` offered by a medium with the applied voltage `'V'` and the passing current `"I"`
`V = IR`
The resistance `'R'` is related to dimensions of the conduc-tor as
`R prop l`
and `R prop 1//A`
`:. R prop (l)/(A)`
or `R = rho (l)/(A)`
where `rho(rho)` is a constant for any material and is called resistivity of the material. the resistivity `(rho)` equals `RA//l` where `R` is the resistance of a uniform conductor of length `l` and cross-sectional area `A`. Itis usually expresseed in `ohm` meters.
Just as `(1)/(R)` is called conductance, `(1)/(rho)` (i.e. the reciprocal of the resistivity is called specific conductance of the conductor. It is represented by the symbol, `kappa`(Greek, kappa). Itis measured in siemeans per mater.