Match List-I with List-II
| List-I Property | List-II Unit |
| (A) Conductivity | (I) S m-1 |
| (B) Molar conductivity | (II) ohm m |
| (C) Resistivity | (III) S |
| (D) Conductance | (IV) S m2 mol-1 |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A) - (I), (B) - (IV), (C) - (II), (D) - (III)
All four quantities come from the resistance of a conductor, R = ρ l/A, where l is the length and A the area of cross-section. Their units follow directly from their definitions:
(A) Conductivity — This matches (I) S m-1. Conductivity (κ) is the reciprocal of resistivity.
\( \displaystyle \kappa=\frac{1}{\rho}=\frac{1}{\Omega\,\mathrm{m}}=\mathrm{S\,m^{-1}} \)
(B) Molar conductivity — This matches (IV) S m2 mol-1. Molar conductivity is conductivity divided by the molar concentration (in mol m−3).
\( \displaystyle \Lambda_m=\frac{\kappa}{c}=\frac{\mathrm{S\,m^{-1}}}{\mathrm{mol\,m^{-3}}}=\mathrm{S\,m^{2}\,mol^{-1}} \)
(C) Resistivity — This matches (II) ohm m. Rearranging the resistance equation gives the unit of resistivity.
\( \displaystyle \rho=\frac{R\,A}{l}=\frac{\Omega\times\mathrm{m^{2}}}{\mathrm{m}}=\Omega\,\mathrm{m} \)
(D) Conductance — This matches (III) S. Conductance is the reciprocal of resistance, and its unit ohm−1 is called the siemens.
\( \displaystyle G=\frac{1}{R}=\Omega^{-1}=\mathrm{S} \)
Shortcut: The pair (D)–(III) appears only in Option (2).